Lack of speech - Concern or no?

17 months old for reference

Can say Mum, Dad, Nan and ‘narna’ for banana but won’t really say Mum/Dad purposely for our attention as such, just when he feels like saying it

Doesn’t really seem to want to copy as you say words (tried all different words/animal sounds which he did used to copy but has since got little interest in copying)

Babbles constantly which is good

Would you be concerned at this age?

No judgey comments please!