This is the 8905th most frequent Turkish word.
söylediğim
"The word 'söylediğim' means 'what I said' or 'that I said' in English."
In this sentence, 'söylediğim' is used as a relative clause referring to 'the thing I said', functioning as the descriptor for 'şey' (thing).
Söylediğim şeyin doğru olduğunu kanıtladım.
I proved that what I said was true.
Here, 'söylediğim' acts as a relative clause modifying 'sırları' (secrets), indicating what was said (the secrets) by the speaker to the listener.
Sana söylediğim sırları kimseye anlatma.
Do not tell anyone the secrets I shared with you.
In this sentence, 'söylediğim' describes 'şarkılar' (songs) as the ones sung by the speaker, personalizing the subject of the sentence (the songs).