I'm on Trello with my gmail account I think the username shows up as leiafee1
I think the barriers are:
Kids put off in school because the mandatory shortcourse is rubbish and teaches you lots of not very useful formulaic stuff. You get very good at filling in the right sort of YES in a box and reciting a few set phrases about your hobbies and that's your lot.
Adults who start learning put off because the default way of doing it a night or two a week Mynediad-Sylfaen-Canolradd-Uwch is SOOOO SLOOOOWWW! I mean it literally feels like you're five years in and still listing the weather and component parts of your family and house.
The attrition rate from WfA is also enormous, possibly due to the above.
The percentage of WfA learners who take part in the Welsh activitie outside the classroom is very very low. In my group of 12 or so in Mynediad there were about 2 of us who did. In Canolradd it was the SAME two and all but 3 of the others had alrady dropped out.
I'm not sure ALL tutors of WfA understand how important that is, or the don't feel confortable pushing it - we were given a log to keep of when we spoke Welsh outside but you got a vibe thst it was a form which had been imposed on them that they weren't entirely comitted to themselves in some classes.
Quality of WfA varies wildly across the country - the Estyn reports are extremely mixed.
WfA for hysterical raisins () follow the school terms - many of the big Welsh language events like the steddfod are in the BREAK in the course which doesn't help at all with encouraging learners to go.
Not all towns have a focus - place everyone knows you can go and speak Welsh Those that do, tend to either be in the hear tof the Bro Cymraeg already or big cities Swansea, Cardiff etc - nothing to the best of my knowledge in e.g. Neath.
FINDING other speakers in some areas is hard which means that learners have to overcome both the "talking a second lanaguge" AND the potential embarassment of pysching themselves up to so do then finding they haven't got a Welsh speaker to talk to after all. The various badge schemes have mixed success so far - Ive had Welsh speakers ask me IN WELSH "Beth yw' comma oren 'na / what's that orange comma thing)
There's a common weird UKIsh hangup that languages are a) hard and b) something you're fundamentally good at or not which doesn't match the reality of how brains work.
Due to the history choosing to learn Welsh is seen as a political act in some quarters, (Which works both ways I suppose)
That's kind of a laundry list of moans I suppose I haven't even started on possible fixes but I can see space for SSIW and volunteers there and it's an exciting challenge. (Much better than arguign with trolls on Twitter who don't get it!)