Linear grammar; Linguistic fossils; Precursor to language; Premodern language capacity; Protolanguage

The term Protosyntax refers in cognitive science to a precursor stage of the human capacity for modern languages. It includes linear phrases with primarily uninflected nouns and verbs.

The notion Protosyntax, also called protolanguage or linear grammar, is a possible window to our understanding of how the modern language capacity might have evolved from single words to complex syntactic structures. It typically refers to a hypothetical precursor stage in the language domain, but in principle, it can also refer to other cognitive capacities such as the Protosyntax of music. The linguistic notion implies that language evolved gradually in the hominid lineage from basic to more complex syntactic structures. Protosyntax uses a linear order of words, is non-hierarchical organized, and lacks inflectional morphology. For instance, it does not use inflections for Tense or Case, is based on semantic combinatory principles such as the perceptual strategy (Agent-First), does not form clusters (hierarchical phrases) to generate questions, passive voices, anaphors, or subclauses as found in fully-fledged modern languages.

Protosyntax, as assumed, is a linguistic fossil that mirrors a possible stage in the evolution of language (see for example Bickerton 1981, 1990; Jackendoff 1999; Progovac 2010; Hurford 2012). One possible implication is that our biological relatives such as Homo erectus (ca. 1.9–0.3 ma) were equipped with a basic language capacity scaffolding a linear word order but not the morphosyntactic complexity of modern languages. In contrast, the oldest fossils of anatomical modern humans more recently discovered in Morocco are about 300 ky old. Our extinct sister species, the Neanderthals (ca. 700–40 ka), had comparable genetic, neurological, and cultural parameters as modern humans, and thus their language capacity was presumably comparable to modern humans (Hillert 2015). One line of evidence finds these structures in emerging languages (e.g., pidgin or sign languages), another line in how children and adults acquire language, how language breaks down, or how these linear phrases resurface in modern languages. Although speculative, research on Protosyntax is highly relevant for the debate on the innateness and origin of the human language capacity (Fig. 1).

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Some languages emerge by the contact of speakers of different languages and who are unable to use a mediating language, a lingua franca, for communication. In Hawaii, for example, various ethnic groups such as Chinese, Japanese, Portuguese, Koreans, and Filipinos spoke at the end of the nineteenth century different pidgins to communicate with the English-speaking population, the Haole (Caucasians) and the native Hawaiians. Since pidgins are not fully-fledged languages but make use of linear syntactic structures, Bickerton (1990) assumes that a pidgin would reflect a protolanguage spoken of early humans or of other Homo species. The linguistic fossils found in pidgin are, however, sometimes less informative for identifying Protosyntax as pidgins are influenced by the speakers’ native languages (e.g., flexibility of word order). Another example is Riau Indonesian, a Malayan dialect spoken by several million people. Virtually, no syntactic categories (nouns vs. verbs) and (almost) no morphology are used, and the word order is based on semantic principles (Gil 2005).

Several newly created sign languages are known, which use a perceptual strategy and lack morphology. One example is home signing. Deaf children create often home signs to communicate with their hearing but not signing parents. Like spoken language, the children go through a two-gesture stage and their developed home sign system is more complex than speech-supporting gestures. Another example, which is well-known, is the Nicaraguan Sign Language, which previously isolated deaf children created in the 1970s from elements of their own diverse home sign systems. The first generation used signs to refer to objects they needed to talk about and stringed them together in phrases. To describe an event, they would sign each Agent followed by his or her role such as “girl push boy fall” or “boy give girl receive.” The next wave of deaf children elaborated on these structures (Senghas et al. 2004). The emerging sign language Sayyid Bedouin Sign Language (Sandler et al. 2005) and the isolated village sign language Central Taurus Sign Language (Caselli et al. 2014) are similar examples.

Traces of Protosyntax, sometimes called “living fossils,” can be also identified in fully-fledged modern languages and how they are acquired and break down. Agrammatic aphasic patients, typical with lesions to Broca’s area, fall back on a perceptual strategy, drop inflections and function words. Child language acquisition includes always a two-word and a telegraphic stage, in which inflections and function words are rarely used. Again, second language adult learners without explicit language instructions show across all examined pairs of native and second languages a protosyntactic stage. Genie, a well-known victim of severe child abuse, who was not exposed to language until the age of 13 years, quickly acquired words after she was found, but her grammar remained behind even years after training.

Specific syntactic structures found in modern languages may also be traces of a protosyntactic stage (see Progovac 2010; Jackendoff 1999). For example, verb-noun compounds without a head (pick-pocket); noun-noun compounds based on concatenations are pragmatically interpretable (cheesecake); free placing of adverbial expressions (apparently or in the morning) can be in initial, medial, or final position of a clause; or small clauses (problem solved!).

The languages so far discussed do not fall all in the same category in terms of morphosyntactic complexity. Modern languages typically use more cognitive resources than creoles or indigenous languages such as Riau Indonesian, which in turn use more resources than emerging languages like pidgins or new sign languages. As we have seen, resources are used to various degrees, but all modern humans are equipped with the cognitive capacity to use these full resources associated with fully-fledged modern languages.

Protosyntax is typically considered as a linguistic fossil, which can be identified in emerging and modern languages, and possibly also in other cognitive domains such as music. This approach, although speculative, is highly intriguing for understanding the cognitive and neurobiological parameters of language processing and how these parameters might have evolved in the hominid lineage. The protosyntactic stage is certainly not the first stage of language evolution as a lexical stage with distinct sound units must precede a syntactic stage. Protosyntax might, however, mirror the premodern language capacity of our biological ancestor Homo erectus. Although alternative scenarios are conceivable, the idea that the “language-ready brain” for fully-fledged modern languages coincides with the birth of anatomical modern humans and their sister species is plausible as is the idea that the “protosyntactic-ready brain” can be associated with Homo erectus. To what extent early modern humans or Homo erectus respectively used their genetically predetermined cognitive resources is a closely related but different issue. In conclusion, current evidence shows that the modern language capacity could not have evolved without the capacity for protosyntactic structures.