Do people "babble" while learning an L2?

Question

I'm currently learning Japanese (みんなさん、こんにちは！), and I've began noticing myself doing the oddest thing while listening to Japanese.

I sometimes find myself uttering back sounds I hear; even when I don't know what's being said. I don't know why I do this; and often don't notice for a good bit.

Something like: "ee watashi wa kono geemu ga atarashii to totemo tanoshiku asobu geemu tte omoimasu ne!"(ええ、私はこのゲームが新しいととても楽しく遊ぶゲームって思いますね！)

Would be uttered back as a vary subtle and hushed: "ee... ko, k-ko no... ee... ata.. atarashii... ee.. to.. temo... tano... aso.. bu.. te... n-ne..."(えー、こ、っこーの、えー、新しい、えー、とー、ても、楽ー、遊ー、ぶ、てー、んーねー)

Am I just weird? Or is this normal? As I've heard people learning English doing something similar; murmuring back what's being said; subtly; without really understanding what's being said.

Is this a thing? Or am I seeing patterns where there are none?

Edit: For the curious; "ええ、私はこのゲームが新しいとても楽しく遊ぶゲームだって思いますね！"(the above version is riddled with errors...) means: "Heh, I think this [game] is a new and vary fun to play game!" with the listener being expected to agree.

Answer 1

I don't know if it's common, but I vaguely remember mumbling or muttering to myself when I was first learning Japanese. In my case, I think it was a way of trying to parse the stream of sounds that I couldn't break down into words and phrases because my vocabulary and knowledge were still too limited at the time.

Assuming the L2 is a living language being studied for the purpose of actually speaking it, I expect some form of attempted repetition of the sounds heard will be quite common. At the early stages, it may very well sound like babbling because the learner isn't capable of putting the sounds together in meaningful units. Also, depending on the degree of phonetic/phonological proximity between the learner's L1 and L2, those sounds may be completly misheard and mispronounced, further making it sound like babbling.

As an interesting contrast, when I worked as an English teacher in Japan, I didn't see a whole lot of attempts at babbling or murmuring back what was heard, but I think that's because a lot of my time was spent teaching junior high school students who had to learn English for their high school exams, people who were being told to take English classes by their employer, or people who saw taking English classes a a hobby but had not real need, or even intrinsic desire, to actually learn.

The anecdotal distinction I observe is that a self-motivated learner who actually wants to acquire the ability to speak in the L2 being studied will inevitably practice one or more forms of (sub)vocalization as part of the learning process. In contrast, people who have the study of a second language imposed upon them by some external agency will rarely do so because they don't actually have an internal desire to be able to use the language.

I'd also expect people studying dead languages such as Latin don't babble a whole lot either, but I imagine you were thinking in terms of learning a second language that's actually in use! :)