I discussed dialogues briefly in an earlier post on expository and naturalistic language. Fasulye suggested in the comment section that dialogues didn't necessarily lead to the use on unnaturalistic language. OK, so I didn't say that it did -- the point I raised was that dialogues aren't a "magic bullet" that makes all language seem naturalistic.
However, that said, I'm not a big fan on dialogues anyway, so today I'm going to talk about how starting a course with dialogues from the very first lesson actually slows down progress for the learner.
The need for a coherent dialogue forces the author to use language that the student isn't yet ready to understand.
The dialogue format forces the learner to move between such a variety of different language, that it forces the student to attempt to learn too many things at once.
I'll use as my example one of the ever-popular Teach Yourself books.
Lesson 1 TY Welsh opens with the following dialogue (my translation)
Matthew: Good morning.
Elen: Good morning. Who are you?
Matthew: I'm Matthew.
Elen: How's things? I'm Elen, the Welsh course tutor.
Matthew: I'm a learner, a very nervous learner!
Elen: Welcome to Lampeter, Matthew. Don't be nervous, everything will be fine.
What do we start off with? It's those old favourites -- hello, what's your name etc.
But what does this teach us?
Let's have a look at the Welsh for "who are you" and "I'm Matthew": "Pwy dych chi?" and "Matthew ydw i".
These two phrases are completely alien to the English speaker. There is only one clue that the English speaker can use to try to make sense of this -- the name "Matthew". A learner might assume that "pwy" and "ydw" are linked, but they're not -- "dych" goes with "ydw", even though the two are not visibly related.
This is the verb "to be", and this problem isn't unique to Welsh -- consider the English "are", "am" and "is". So even when we look at dialogues from an entirely expository point of view, we have a problem that means we have too many unknowns for the new learner.
Consider the following (not a real example) as though it was in lesson one:
John: Are you tired?
Sally: Yes, I am tired.
You as a learner are asked to contrast the question with the answer, but we have a massive amount of variation in a very simple sentence. First of all, we have the matter of the irregular verb forms, as above. Secondly, the pronouns are radically different (as in most languages). Finally, we have a change of word order. Learners could confuse their verbs and pronouns, and miss the word order entirely.
OK, that's not a real lesson 1 example, but I've already given a worse example from the Welsh course - Pwy dych chi?. In the Welsh, the word order doesn't change for the answer Matthew ydw i, but that's arguably as difficult for an English speaker as English word order is for speakers of a language that doesn't change order. We also have no repeated recognisable word form to highlight any the word order in Welsh. There is an awful lot of rules in play here, each interacting to make the full meaning of the sentence. Without seeing these in isolation, the role of individual elements is obscured.
And it's even more complicated in French. Many courses will introduce Comment t'appelles tu? and the response Je m'appelle Jean-Pierre (or whatever name). This introduces the complication of the reflexive pronoun, which is a version of the object pronoun. Well, actually, the reflexive pronoun is identical to the normal object pronoun for "me" and "you", which actually makes this more confusing. While the change of word order for the question is theoretically the same as English, the lack of auxiliary do (eg Do you know?) in French questions makes it completely different to the untrained eye. The fact that this places the object before the subject is particularly alien to the English speaker. This is massively difficult, and so the learner is only expected to memorise or learn to recognise the phrase. The assumption here is that by exposure to later examples, the learner will induce the underlying patterns, but this is something that dialogues are actually very bad at.
Dialogues by their nature attempt to model naturalistic conversations, and this leads them to include a very wide variety of language. Unfortunately, variety means very little repetition, so there is very little material to induce the rules from. It gets worse when the writer is trying particularly hard to be naturalistic, because many of the expository cues are lost. Remember this from earlier? I'm a learner, a very nervous learner! Notice that this uses elision (the ommission of repeated words) for increase naturalisticness, but missing the opportunity to reinforce the structure "I am".
French courses rarely follow up the je m'appelle with any other reflexive constructions -- the only thing it is contrasted with is usually il/elle s'appelle (he/she/it is called). The student is left knowing the phrase for a long time without being given the input to learn why it means what it means. In fact, this risks interfering with normal (non-reflexive) object pronouns, because the learner is overexposed to the reflexive form, and unexposed to the base form for a long time.
The root cause of the problem
The language in a naturalistic dialogue is linked by context, and elision is a major feature of natural language.
In short, we actively avoid repeating language in a conversation.
This leaves us teaching language that is only bound by context, so is semantically reinforcing, but not syntactically reinforcing.
If we progress in a language by learning a new word, it opens up a few extra possibilities, but learning new grammatical structures can double our knowledge of the language.
So imagine you know "I like...", "I have..." and "cars", "trees" and "dogs" -- you can say 6 combinations. If you next learn to say "cats", that's an additional two sentences -- "I like cats" and "I have cats" -- so 8 in total.
But if instead you learn the negation "don't", that doubles the number of sentences to 12.
Massive growth in beginner language is only possible if you focus on teaching language points that can be combined within a sentence to make bigger and more complicated sentences. The dialogue format militates against this, and after one dialogue-based lesson, a learner is not likely to be able to produce even as much as is in the dialogues themselves. Compare with the Michel Thomas courses where (even excluding the -ible/-able words) the learner has a range of expression that while limited still covers dozens of different possible sentences. By building on this, the student experiences almost exponential growth. That's cool.