The irregular plurals of French have received little attention in the literature, perhaps due to a prevalent intuition about their lack of productivity. Indeed, the alternation is synchronically unnatural, and does not seem to extend to loanwords. The number of [al/aj]-final monosyllables is rather small (n = 16), and thus might not intuitively suggest overwhelming evidence for their protection. We present a series of three experiments that establish that French speakers do extend the alternation to nonce words, and in particular, strongly protect the monosyllabic ones.
In Experiment 1 and Experiment 2, we asked participants to choose between a faithful plural and an unfaithful plural. The choice is presented on a scale of 1–7 in Experiment 1, and binarily in Experiment 2. In both experiments, the nonce words are presented auditorily using naturally produced speech. Additionally, in Experiment 2, participants were asked to rate the singular before they judge the plural. In both experiments, monosyllables were protected from alternation.
In the naturally produced materials of Experiments 1 and 2, the phonetic duration of the final [al/aj] sequences is inversely proportional to the duration of the whole word. Thus, the [al] of the short word [gnal] is phonetically longer in duration than the [al] of longer word [guval]. Increased segmental duration has been suggested as a source of protection from alternations, thus making the [al] of monosyllables less likely to change to [o] (see Sect. 6). In Experiment 3, we switch from naturally recorded stimuli to synthesized stimuli that keep segmental duration constant, i.e. the [al] of [gnal] and the [al] of [guval] were identical in duration. Participants nonetheless protected monosyllables; the implications are discussed further in Sect. 6.
Experiment 1: Scalar judgments
The participants were recruited online using word of mouth, and volunteered their time and effort without compensation. Data was gathered from 185 people who completed the survey and self-identified as being born in France and being at least 18 years old; the rest was discarded. The server logs indicate that these 185 participants took on average 4 minutes to complete the experiment (range 2–17 minutes; median 4). The participants reported an average age of 36 (range 18–74, median 32). According to self-reports, 116 females and 65 males completed the experiment; 4 did not answer this question. 83 participants listed no other language spoken, or indicated that they are monolingual. Of those who listed other languages, 76 indicated some knowledge of English, 18 Spanish, 15 German, and small numbers of other languages.
We created a total of 100 [l/j]-final items: 66 items with [a] in their final syllable (36 monosyllabic and 30 polysyllabic) and 34 items with [ε] (18 monosyllabic and 16 polysyllabic); recall that alternations in the lexicon are largely limited to [a] as compared to [ε], and we included the latter as a baseline for comparison. All nonword items were made in pairs, with [l] in one member and [j] in the other, e.g. [snal, snaj]. The items’ onsets were designed to span a wide range of phonotactic wellformedness, from extremely common onsets like [d] and [ʁ] to extremely uncommon ones like [sn] and [spʁ] (see discussion of this point in Sect. 6). The full list of items, with by-item results, is in Appendix B. 12 loanwords from English were used as fillers, e.g. [stεk] ‘steak’, [dolaʁ] ‘dollar’.
The items were recorded by a phonetically trained male native speaker of French in his twenties from the Ferté-Bernard region (∼100 miles from Paris) who was naive to the purpose of the experiment. The list included each noun in the faithful plural (which in French is identical to the singular) and the unfaithful plural, which replaced [al, aj, εl] with [o] and [εj] with [ø]. The recording was made in a quiet room into a Macintosh computer. The full list was recorded in three randomly generated orders. The best token of each item was chosen and converted to mp3 format. The recordings were not manipulated in any other way, other than normalizing the intensity with Praat (Boersma and Weenink 2015), and sounded natural.
The experiment was run in Experigen (Becker and Levine 2012), and presented to the participants over the internet, using the web browser of the participant’s choice. The web server executed a random selection of materials for each participant, choosing a total of 20 items: 12 target items and 8 fillers. The experiment started with the sample item [dal], which we include in the analysis.
In addition to [dal], the 12 selected target items consisted of six monosyllables and six polysyllables, where each size included 3 [al]-final, 1 [aj]-final, 1 [εl]-final, and 1 [εj]-final items. The choice of more items containing [a] than [ε] reflects our expectation for a greater rate of alternations in the former. The choice of more [al] than [aj] approximates the greater prevalence of [al] in the lexicon. An additional 8 fillers were chosen randomly.
To make sure that the items were treated by speakers as masculine nouns, 20 frame sentences were created (recall that feminine nouns do not alternate). Each frame contained two phrases: the first included a placeholder for a singular noun, and the second included a placeholder for the plural form. Each frame contained at least one determiner or adjective that has phonologically distinct masculine and feminine forms, e.g. [gʁi] ‘gray.masc’, which is distinct from [gʁiz] ‘gray.fem’. These 20 frames were randomly paired with the 12 target items. Frame sentences were created for each of the 12 fillers.
Before the experiment began, each participant was introduced to the made-up item [dal], and was asked to indicate their preference between a faithful plural and an alternating plural, presented in French as a choice between “pluriel en s” and “pluriel en x”, referring to French orthography, which marks regular plurals of l/j-final nouns with 〈s〉 and vowel-changing irregular plurals with 〈x〉. In the following screen, the item [dal] appeared in its frame sentence, as schematized in Fig. 2. A sound button played the plural [dal] when pressed, and upon completion, another sound button appeared. When pressed, the plural [do] was played, and the question “Which plural do you prefer?” appeared, with seven numbered buttons. The edges of the scale were labeled “the one on the left” and “the one on the right”. Once one of the seven buttons was pressed, a new screen with the next item appeared.
The order of presentation of the two plurals was randomized. After participants responded to the randomized list of 20 target items and fillers, they were asked to answer demographic questions (country of origin, current location, year of birth, sex, other languages spoken, suggestions).
On average, speakers demonstrated an asymmetry in the treatment of monosyllables, preferring faithful plurals for monosyllabic items and alternating [o/ø] plurals for polysyllabic ones (3.5 vs. 4.3 on the 1–7 scale). In addition, they preferred faithful plurals with [ε] and alternating plurals with [a] (2.7 vs. 4.4); this comparison simply reflects the distribution based on vowel quality found in the lexicon. Both of these effects can be seen in Fig. 3, where error bars show 95 % confidence intervals. Figure 3 also shows an interaction: the monosyllabicity effect is much stronger for [a] than it is for [ε]. The difference between [j]-final and [l]-final items was overall rather small (3.6 vs. 4.0). The raw results are available at http://becker.phonologist.org/projects/FrenchPortuguese/.
To assess the statistical strength of these effects, a mixed-effects linear regression model was fitted using the lmer function from the lme4 package (Bates and Maechler 2013) in R, with rating of the alternation as the dependent variable.Footnote 7 The following predictors were used: monosyllabic, a binary predictor that contrasted monosyllables and polysyllables, vowel, a binary predictor that contrasted [a] with [ε], and consonant, a binary predictor that contrasted [l] with [j]. A fully crossed model is reported in Table 2.Footnote 8 The model confirms that alternations are significantly dispreferred with monosyllables (negative β) and significantly preferred with [a] relative to [ε], just as expected based on the lexicon (Sect. 2). A significant interaction shows that the effect of monosyllabicity is stronger with [a]. The difference between [l] and [j] came out as a weak trend, suggesting that the two consonants may be equally deletable.
The experiment confirms that speakers have access to the lexical trends that we described in Sect. 2, and that they extend these trends from the real words of their language to novel words. We will show in Sect. 3.4 that the lexical predictions are strongly correlated with the experimental results. In particular, speakers prefer the alternation in polysyllabic words, keeping monosyllables relatively protected.
The lexical trends are projected from the lexicon even though the alternation is no longer productive or natural, and thus from the linguist’s perspective, there is no clear benefit to encoding the size-based faithfulness effect in the synchronic grammar. The discrete and grammatical treatment of this pattern is apparently irresistible to the learner, who generalizes over the lexicon using salient grammatical principles, even if those generalizations no longer apply to existing words over a natural alternation.
Experiment 2: Binary judgments
Experiment 1 established that French speakers prefer alternating plurals most in polysyllables that have [a] in their singular form. Two questions remain, however. Firstly, it is not clear what role the wellformedness of the singular might have on the choice of plural. Secondly, the use of a linear regression in the analysis of responses on a 1–7 scale is potentially problematic, because it assumes that participants are using the scale linearly (i.e., the distance between 1 and 2 reflects the same difference in acceptability as the distance between 2 and 3, etc.). To alleviate these concerns, the next experiment asked participants to rate the singular base before they judge the plural forms. Plural forms are presented for judgment in a binary yes-or-no task, to be analyzed with a logistic model. The materials and methods were kept exactly the same as in Experiment 1, with the sole difference being in the format of the individual trials.
The participants were recruited online using word of mouth, and volunteered their time and effort without compensation. Data was gathered from 52 people who completed the survey and self-identified as being born in France and being at least 18 years old; the rest was discarded. The server logs indicate that these 52 participants took on average 7 minutes to complete the experiment (range 3–27 minutes, median 5). The participants reported an average age of 32 (range 22–66, median 30). According to self-reports, 31 females and 21 males completed the experiment. 9 participants listed no other language or indicated that they are monolingual. Of those who listed other languages, 41 indicated some knowledge of English, 13 Spanish, 10 German, and smaller numbers of other languages.
The materials are identical to those of Experiment 1.
Each item was first presented in the singular, in a frame sentence (as in Experiment 1), but with the singular written on a button. Pressing the button played the singular form and then a question was displayed, asking the participant to rate the item as a word of French on a scale of 1–5, as shown in Fig. 4. Once one of the 1–5 buttons was pressed, all buttons were disabled (turned gray and unpressable), and one of the plurals (either faithful or alternating, randomly chosen) was presented in a frame sentence containing a sound button. When pressed, the plural was played, and a question was displayed, asking the participant whether the plural was acceptable (yes or no). Once one of the two buttons was pressed, both were disabled, and the other plural was presented in the same way, again asking for a yes or no judgment of its acceptability. Pressing one of the final two buttons then moved the participant to the next item.
As in Experiment 1, speakers accepted the alternating [o/ø] plurals with monosyllabic items significantly less than with polysyllabic items (40 % vs. 55 %). In addition, they accepted alternating plurals with [a] significantly more than plurals with [ε] (55 % vs. 29 %). Both of these effects can be seen in the bar plots in Fig. 5b. Figure 5b also shows an interaction: the monosyllabicity effect is much stronger for [a] than it is for [ε]. The difference between [j]-final and [l]-final items was overall rather small and insignificant (41 % vs. 50 %), and it was even smaller for the [a] items (59 % vs. 54 %).
In this experiment, speakers also rated the singulars on a scale of 1–5 before they judged the plural forms, seen in Fig. 5a. Overall, participants found the singulars to be of intermediate acceptability (3.0 on the 1–5 scale). Polysyllables were rated higher than monosyllables (3.2 vs. 2.7), and items with final [l] were rated higher than items with final [j] (3.0 vs. 2.7). Items with [ε] were rated slightly higher than items with [a] (3.0 vs. 2.9). This small difference between [ε] and [a] confirms that speakers successfully separated the rating of the singulars from the acceptability of the plural forms.
The acceptability of the faithful plurals mirrored the acceptability of the alternating plurals, so we do not report these here. The complete raw results are available at http://becker.phonologist.org/projects/FrenchPortuguese/.
The acceptability of the alternating plurals was modeled with a mixed-effects logistic regression, using the following predictors: base, or the acceptability of the singular base on the 1–5 scale, and the full crossing of the three predictors monosyllabic, vowel, and consonant, defined as in Experiment 1, and reported in Table 3.Footnote 9
The model in Table 3 shows that alternating plurals are highly significantly preferred in polysyllables and with [a], including a significant interaction. The difference between [l] and [j] did not reach significance at the .05 level. The correlations of base with the other predictors were very low (r<.14), suggesting that the observed effects of monosyllabicity and stem vowel go above and beyond the rating of the singular base. To confirm this point, we factored out the potential correlation of base with monosyllabic and vowel using residualization, i.e. taking the remaining predictive power of base once it did its best to predict monosyllabic and vowel; the residualized model is essentially identical to the one reported here.
Overall, this experiment confirms and replicates the results of Experiment 1. Experiment 2 sharpens the interpretation of the results of Experiment 1 in two ways: Firstly, the singular base form was rated on its own, in addition to the plurals. The regression results suggest that the protection of monosyllables is statistically independent from the phonotactic wellformedness of the base. Secondly, the plurals were judged binarily, and thus could be modeled statistically using a logistic regression. This alleviates the potential concern about modeling a scalar rating using a linear regression. Importantly, Experiment 2 confirms the three strong effects found in Experiment 1: the difference between monosyllables and polysyllables, the difference between [a] and [ε], and their interaction. Neither experiment showed a significant effect of the final consonant. In short, the grammatically-mediated difference between monosyllables and polysyllables in nonce plural formation was robustly upheld with a wholly different rating methodology.
Experiment 3: No duration cues
Cross-linguistically, monosyllables are usually produced with segments that are phonetically longer than segments in polysyllables; this trend holds true in French generally, and it holds of the materials used in Experiments 1 and 2 specifically. Thus, a monosyllable such as [gnal] has a phonetically longer [al], while a disyllabic [guval] has a phonetically shorter [al]. As will be discussed in Sect. 6 below, longer segmental duration has been proposed as a source of protection from alternations, and according to this view, our materials in Experiments 1 and 2 provided participants with a phonetic cue that could be used in the judgments of the plural forms. To control for this effect, the current experiment uses artificially created auditory stimuli that maintain constant segmental duration; the experiment is otherwise identical to Experiment 2.
The participants were recruited online using word of mouth, and volunteered their time and effort without compensation. Data was gathered from 71 people who completed the survey and self-identified as being born in France and being at least 18 years old, discarding the rest. The server logs indicate that these 71 participants took on average 6 minutes to complete the experiment (range 3–18 minutes, median 5). The participants reported an average age of 35 (range 19–79, median 31). According to self-reports, 46 females and 22 males completed the experiment; 3 did not say. 5 participants listed no other language or indicated that they are monolingual. Of those who listed other languages, 62 indicated some knowledge of English, 25 Spanish, 14 German, and smaller numbers of other languages.
The same words were used as in Experiments 1 and 2. The auditory materials were not recorded by a native speaker, but rather generated by the mbrola text-to-speech system (Dutoit et al. 2006). Vowels were generated specifying a level pitch of 130 Hz, and a duration of 280 ms in final (stressed) position and 140 ms in non-final (unstressed) position. Consonants were specified with durations ranging from 80 ms to 160 ms, depending on their identity, but not on their position. The pitch and duration values were chosen to match the averages obtained from the naturally produced materials. The materials, then, had identical final syllables in, e.g. [zal] and [vøzal]. While the resulting materials sounded decidedly robotic, their segments were easily recognizable.
The procedure is identical to that of Experiment 2.
The results are overall similar to those in Experiment 2, with alternating plurals being accepted more with [a] than with [ε] (55 % vs. 17 %), with [l] more than with [j] (48 % vs. 32 %), and with polysyllables more than monosyllables (48 % vs. 39 %), as seen in Fig. 6b. Again, the ratings of the singulars show a preference for polysyllables over monosyllables (3.5 vs. 3.1 on the 1–5 scale), for [l] over [j] (3.4 vs. 3.1) and for [ε] slightly more than [a] (3.4 vs. 3.2), as seen in Fig. 6a.
The statistical analysis was performed as for Experiment 2, and reached similar results.Footnote 10 The final model in Table 4 shows that alternating plurals are significantly more acceptable when the rating of the base is higher and with the vowel [a]. More importantly, alternating plurals are accepted significantly more often in polysyllables than in monosyllables. There was no significant interaction of vowel and monosyllabicity.
As reported for Experiment 2 above (Sect. 3.2.4), we found that residualizing monosyllabic and vowel against base makes very little change to the model for Experiment 3, confirming that the preference for alternating plurals in polysyllables goes above and beyond the preference for polysyllabic singulars. We also fitted a regression model for the combined results of Experiment 2 and Experiment 3, with an added experiment factor; this combined model is only minimally different from the ones we report for each experiment individually, and no significant difference between the experiments was found.
Comparison of lexicon with experimental results
The three experiments confirm that speakers prefer alternating plurals when they are polysyllabic, and faithful plurals when they are monosyllabic. Experiment 2 and Experiment 3 also show that this preference goes above and beyond the higher ratings given to polysyllabic singular bases. Experiment 3 confirms that speakers prefer alternations in polysyllables even in the absence of segmental durational cues for monosyllabicity in the auditory materials they heard. This result shows that speakers have their own internal expectations about the distribution of plural alternations and that these expectations do not require support from the phonetic properties of the particular tokens presented to them.
All three experiments also showed a preference for alternations with [a] relative to [ε], as expected. There was a significant interaction of vowel and monosyllabicity in Experiments 1 and 2. In Experiment 3, a much larger estimate for the vowel effect left the interaction insignificant.
Comparing the predictions of our MaxEnt analysis in Sect. 2.3 to the participants’ responses per item, we see a strong and highly significant correlation, shown in the three panels of Fig. 7; the Spearman rank correlation coefficients are .78, .56, and .72 for the three experiments, all significant at p < .001. The lowest correlation, which is still rather strong, is found in the experiment with the smallest number of participants. Differently stated, there is a close match between the predictions of our lexicon-trained grammar and the observed treatment of nonce words. Our model by no means captures the entirety of the variance in the experimental results; in particular, there is a great deal of variance within each of the categories imposed by the MaxEnt model. It is thus possible that the prediction could be further improved perhaps using more fine-grained details regarding onset profiles.
The three experiments did not show a significant effect of final consonant. This result was somewhat unexpected given the predictions of our lexicon regression model and our MaxEnt analysis, and the general expectation that lexical trends usually extend to nonce words (Hayes and White 2013, contra Becker et al. 2011). We suggested that this “surfeit of the stimulus” case is due to the sonority hierarchy: if deletion of low-sonority segments is categorically blocked, speakers are biased to extend this trend upwards in the scale, not allowing liquids to be more deletable than glides. This effect can be incorporated into the MaxEnt analysis with a defeasible Bayesian prior that requires the weight of Max(glide) to be closer to zero. However, an additional explanation suggests itself: recall footnote 2, in which we mentioned the collinearity of final consonant with part-of-speech. Should learners opt for part-of-speech as the relevant generalization and completely ignore final consonant as a result, no effect of final consonant would be expected in our experiments. To test such a hypothesis, one would need to design an experiment explicitly contrasting l-final nouns and adjectives.
We conclude this section by focusing on the importance of the monosyllabic vs. polysyllabic effect in determining whether a noun will undergo the irregular plural alternation in French. In the next section, we turn to a parallel alternation in Portuguese, where the details of historical development are different. In particular, while the alternation is no longer natural in either language, the Portuguese alternation is very much alive, extending productively to polysyllabic words and loanwords.