Thank you Nodda! I read your post back when you made it, and it has helped with my motivation. Since hitting 108 bpm back in mid-February, I have kept up my 10 minutes a day of single articulation practice, and now I'm up to 115 or so. Woo! I'm hitting plateaus more often now, and they last a little longer, but usually after 5 or 6 days I can see some sort of improvement. I've gotten a lot better since February - I now warm up my articulation exercise at 110 and speed it up in 2's, then 1's from there. So now I can start cold at a faster speed than I had been stuck at
And I totally agree with your excellent point on playing longer pieces at slightly slower tempo. The first few pieces in the RCM Level 5 book are heavy on articulation, and the tempo listed is 100-108, so I got them up to 104 and played each for almost a week at that speed. That greatly strengthened my tongue - mixing in the slurs helped break it up, but nearly 2-3 mins of quick single tonguing did wonders.
Thanks for sharing that it took you about 11 months to go from 100 to 120 bpm. I'm now closing in on 4 months, and it will probably be at least another month until I can regularly get up to 120, and it will probably be several more until I'm comfortable enough with it to play a piece near that speed without undue effort.
Thank you again! And best of luck with your work to keep speeding up your tonguing speed!