Chomsky's idea wasn't that there was a strong inductive bias in language learning, it was that language isn't learned at all; it grows in the brain, as his accolyte Pinker claims, "like teeth grow in the mouth." You don't "learn" to have teeth, do you?, Pinker asks.

How can this be, when we see so obviously that kids raised by Greek speakers learn Greek while those raised by English speakers learn English?

It's because, acc. to Chomsky and his followers ("Modern Linguists"), Greek and English are really the same language, and kids don't LEARN this language, called "Universal Grammar," they GROW it. What they DO learn is the values of some "parameters" that cause different instantiations of UG to appear superficially different, like Greek and English.

This quickly required the definition of "language" to exclude every aspect of language except syntax, because everything else so obviously was learned and wasn't universal, and even with syntax, they ended up having to exclude the syntax actually used by real speakers really speaking. That syntax become known as "performance" as distinct from "competence", which was the universal language people really knew deep down inside but which got corrupted in real use by various noise-inducing factors.

So "real language" became syntax only, and then, only carefully constructed written examples of proper, uncorrupted "competence" syntax. And with those, all native speakers could use their innate rules plus parameter settings to unanimously agree on which word sequences were valid and which were invalid. You had a rule-based syntax with universal rules, right?

Except that, with each passing year, researchers outside the linguistics departments found more and more examples where native speakers disagreed over validity, and validity decisions that weren't discrete (clearly valid or clearly invalid) but were often shades of gray. (Inside linguistics departments, conformity to Chomskyism orthodoxy was usually enforced, as academia tends to do, so "linguistics research" has supported Chomsky for decades, while cognitive science hasn't.)

There were so many differences among native speakers of a single language, not to mention the ever-growing catalog of diversity between languages and the way that languages gradually diverge instead of in clearly discrete jumps, and so many shades of gray in judgments among natives that the notion of parameters got more and more ridiculous, even with the notion of "language" pared down to almost nothing.

Sure, you could claim that all books are the same universal book, too, as long as each character is a parameter. If so, then all languages are the same language under the surface, too, plus or minus some parameter settings.

Chomsky's ridiculous language ideas would have been thrown out long ago if he hadn't been such a leftist "intellectual icon" in the leftist temples of academia and media. Instead, his theory just changed dramatically from version to version but remained unquestionably true throughout. Every few years he would significantly revamp his "program." In 2002 he seemed to abandon everything about syntax, too, except for recursion. What's unique about human language, as opposed to the general principles found in all human (and some animal) cognition, is just the innate, universal ability to handle recursion in syntax. (That paper apparently infuriated Pinker by cutting his "Language Instinct" position down to just a syntactical recursion instinct.)

What a bunch of nonsense. And this paper is just one more nail in the coffin of "modern linguistics".