Coins begone

It says I earn coins prior to completing lessons, however, they go down after each lesson. Also, how does the text to speech option work because one moment it seems to be my correct choice but in the other its changed.

Coins earned shouldn’t go down when you complete a lesson. When you create a LingQ or make a word known you earn coins. The number of coins you earn depends on the value of the word. The most common words are considered more valuable and are worth four coins. The less common a word is, the fewer coins you will earn.
If you complete a lesson and you have some blue words left in a lesson, all blue words will became known and you should actually get more coins for them. Can you check that one more time and let me know what exactly happens?
Regarding TTS, are you referring to Review? Dictionary test? Can you please give me more details here too? Thanks!

It was my ignorance I believe, but yes in reference to review. Also, the coin thing is a bit odd because I will have 2k once then 800 the next lesson.

Thank you for responding