I'm aware I'm going to be slightly off-topic, and I know I'm not going to answer in the end, but OP's question raises several issues that ultimately affects that of the name and my point is much too long for either a comment or sentence in the chat room.
only 15% self-declared as professional or academic
15% might be overrated, I'll explain. I agree with OP's use of the word "professional" here but I'd like to point out that the term used in commitment, choice & statistics, is "expert" and not "professional" and that can make a huge difference. Few people who are not professionals will declare themselves as "professionals", whereas lots of people might declare themselves as "experts" just because they speak the language.
Being a native of a language, or just being fluent in a language does not mean one is an expert at teaching the language*. Teaching a language not only requires some knowledge of the language but expertise in teaching methods, and the expertise in teaching is more important than the expertise in the language. Teaching a language does not only involve knowledge of the language but knowledge in neurobiology (process at work when listening, memorising, etc.), acoustics, phonetics, and lots of other things. OP makes the point himself at the end of his question:
It would be especially interesting to hear from people who are in some way experts in language learning, such as teachers.
Now about the name:
"Language learning" does not indeed come across professionals who are teachers, I do not think "language study" would work any better, neither term include the process of transmission that is implied in teaching, teaching implies interacting with someone else in order to pass on some specific knowledge. A learner can learn without a teacher but a teacher cannot teach without a learner, thus "language teaching" would be more relevant but would the learners' part of the site feel concerned and it would it be really sufficient to attract professionals?
"Language teaching and learning"? Not so much of a mouthful (it would soon be LTL) but there again would it be sufficient to attract professionals?
Academics this site is trying to attract - or so it seems to me - are specialists of SLAT (Second Language Acquisition and Teaching). It's the denomination used in international communication, English being the language of exchanges in oral communication and academic papers on this topic.
The word "learning" alone will not attract SLAT professionals at first glance and if one wants to advertise and boost search engines, then it needs something catchy.
This is my contribution to SLAT search by bots, but acronym SLAT being used for other things expansion is needed at some point.
* And this is really an issue in countries where the lack of trained language teachers is tackled by employing natives of the language who have no training.