Problems with vocal tracks

Hi all - when I input a vocal track using my midi keyboard, the notes are ‘sung’ using the default ‘doo doo’. I then go into each note and add the lyric, but when I then play the track back, the notes with a lyric go silent (they aren’t deleted, they just stay muted). The only notes that sound, are the default ‘doo doos’. This is a complete mystery, and never used to happen. I haven’t changed any settings at all. Please help if you have an answer, it’s probably something crazy I’ve missed!

Have you selected a voice bank? I guess so, but default lyric for me is “aah”.
Could you have adjusted note lengths such that they overlap (greyed out)?

Hi - thanks for the reply. I’ve just solved it! I was typing the lyric into the box above the midi note, rather than into the note itself - I thought it was operator error!!