Also relevant in this regard is the following passage from Popper 1959.

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There is only one way to make sure of the validity of a chain of logical reasoning. This is to put it in the form in which it is most easily testable: we break it up into many small steps, each easy to check by anybody who has learnt the mathematical or logical technique of transforming sentences. If after this anybody still raises doubts then we can only beg him to point out an error in the steps of the proof, or to think the matter over again. In the case of the empirical sciences, the situation is much the same. Any empirical scientific statement can be presented (by describing experimental arrangements, etc.) in such a way that anyone who has learnt the relevant technique can test it.
(Popper 1959: 99, the emphasis by HH)
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We cannot emphasize more the significance of what is intended above. When we make an empirical claim/hypothesis about the nature of the language faculty, we should present it, in principle, with a design of (a) experiment(s) by following which we/one can test whether it makes (a) correct prediction(s).

It is equally important to stress that it would not be enough just to agree with and endorse the above statement. What counts is whether one puts it into practice. If you agree with Popper's remark above, you might want to ask whether or not the most recent work that you read (fairly) carefully indeed does that. If the answer is yes, you should be able to conduct, or at least have a fairly clear idea about how to conduct, the relevant experiment(s) to test the predictions made in that work.

(My Lingua paper does not quite provide explicitly how the relevant experiment can be done. I suspect that it should not be very difficult to 'design' the relevant experiments, on the basis of the discussion there. But when we try to actually do it, we might find it more difficult than we expected.)