Try this thought experiment:

A couple learn an invented language and use it with their child who picks it up naturally. The child eventually meets another person who has the same artificial mother tongue. To what extent will they be able to communicate? That is to say, to what extent will the two linguistic systems be aligned?

Or this one:

Two people, each with different L1s, learn to communicate in a lingua franca for which there are no prescribed rules of suprasegmental phonology, such as rhythm and intonation. Will they be mutually intelligible?

Or this one:

An artificial language has been developed that has its own grammar and vocabulary, but not a codified phraseology, e.g. of collocations, idioms, etc. Will a phraseology develop naturally through use? And to what extent will this cause communication breakdown between speakers of the language who have learned and used it in different settings?

As it happens, these ‘experiments’ are regularly put to the test whenever speakers of artificial languages, such as Esperanto, interact. Designed to be an international lingua franca, Esperanto never quite fulfilled its utopian promise, but (according to Wikipedia) ‘up to two million people worldwide, to varying degrees, speak Esperanto, including about 1,000 to 2,000 native speakers who learned Esperanto from birth.’ This last fact must surely excite researchers of second language acquisition and of sociolinguistics, specifically that aspect of sociolinguistics that deals with generational language change. It’s surprising, therefore, that there is little or no mention of Esperanto in the literature of either SLA or sociolinguistics.

The second generation speakers of Esperanto (I would have thought) would provide interesting data for those who are concerned with how language acquisition emerges, especially in conditions where opportunities for input and output are restricted – which is often the case, not only for speakers of Esperanto, but also for learners of EFL. And it might provide insights into how languages evolve over time within particular speech communities.

For example, it has been shown (Bergen 2001) that children who grow up speaking Esperanto tend not to use the accusative case. (The accusative case is the marking of nouns and adjectives as objects of the verb. In English, the accusative survives in only a handful of pronouns, e.g. who vs whom). Native speakers of Esperanto also ignore a number of complex tense and aspect distinctions that are marked with affixes.

How does one account for these divergences from ‘proper’ Esperanto (i.e. the language learned by their parents) and the language spoken by second generation Esperanto speakers? Are the differences attributable simply to L1 transfer – given the fact that native Esperanto speakers are invariably bilingual? Or is the ‘nativization’ process determined by general (i.e. not language-specific) learning strategies, such as a tendency to overgeneralize rules or to eliminate redundancy? Or is the failure to adopt features of the target grammar, as prescribed by its grammarians, simply an effect of incomplete learning, due, perhaps, to limited exposure and opportunities for use – what SLA researchers might call the premature stabilization of the interlanguage? Indeed, can we talk about ‘interlanguage’ at all, given that there is no agreed ‘end state’ in the acquisition of Esperanto, i.e. there is no native speaker model that has been codified over generations of users?

Or can second generation Esperanto be explained only by recourse to an innate, language-learning faculty, such as argued by proponents of Universal Grammar (UG)? Could it be that second-generation Esperanto offers evidence of universalizing principles? Which also raises the interesting question as to whether any of the features of Esperanto grammar contravene UG, and, if so, have they been shed in the process of nativization? (Another thought experiment: a language is devised which contravenes UG – e.g. has ‘postpositions’, rather than prepositions (‘the bus on’, not on the bus), but has adjectives before rather than after the noun, i.e. a red bus, not a bus red. It is taught to one generation and then acquired by a second. Would the word order discrepancies resolve themselves? If so, in which direction?)

The accusative case, incidentally, has an interesting history in Esperanto: Zamenhof – Esperanto’s designer – believed that the presence of accusative forms of nouns and adjectives would allow a more flexible word order. Thus, with accusative markings, the difference between The dog bit the girl (‘La hundo mordis la knabinon’) and The girl bit the dog (‘La hundon morbis la knabino’) requires no change in word order. But, as early as 1895, there was a heated discussion as to its usefulness. So Zamenhof put it to the vote. The ‘accusativists’ won, triggering a separatist movement within Esperanto, and the formation of a breakaway language called Ido, which abandoned the accusative altogether. As we have seen, nativized Esperanto speakers have tended to follow suit.

Esperanto also offers a suggestive precedent for other (theorized) lingua francas, such as ELF (English as a lingua franca), which have no associated culture and few if any native speakers. Thus, the phonetician, John Wells, an accomplished Esperantist himself, has used the case of Esperanto to argue that speakers of a lingua franca for which there is no codified system of intonation (like Esperanto, like ELF) will simply adopt and adapt the intonation of their L1, with little or no prejudice to intelligibility. This is an argument against the explicit teaching of intonation, especially in the teaching of ELF (see the discussion in I for Intonation). On the other hand, transferring idiomatic expressions from an L1 into a lingua franca (such as Esperanto or ELF) should probably be avoided, since these are unlikely to be transparent to one’s interlocutors – a case against teaching phrasal verbs, for example.

In short, Esperanto, even if not the success its original proponents had envisioned, offers suggestive material for re-imagining the acquisition and teaching of English.

Reference

Bergen, B. K. (2001) ‘Nativization processes in L1 Esperanto.’ Journal of Child Language, 28.