Your pleasant thoughts were about "being able to speak Swahili" rather than "learning Sawahili". Your thoughts were about the joy of the reward, which I guess are not reinfornced in total independence from actions (imagine trying to learn Swahili without the rewarded thoughts, you'd probably not make it through th first few calsses), but are certainly not identical.

What would happen if you think about the effort of actually learning? Will it get negatively reinforced the same way as actually doing the effort?