AVSpeechSynthesizer is describing certain words rather than just speaking them

Problem: AVSpeechSynthesiser sometimes describes words rather than just speaking them as a real person would.

When speaking in English AVSpeechSynthesiser pronounces the word "A" on its own as "Capital A", while the phrase "A little test" is pronounced correctly.

A workaround of lowercasing the speech string - so "A" becomes "a" fixes this specific example. (I'm not yet sure if lowercasing sentences could affect pronunciation badly in some instances.)

A more serious example: When speaking French the word "allé" on its own is pronounced by AVSpeechSynthesiser as "allé - e accent aigu" (accent aigu = acute accent). And here the problem exists even when the word is part of a sentence!

With "Je suis allé au cinéma" (I went to the cinema)

AVSpeechSynthesiser says "Je suis allé e accent aigu au cinéma" which is clearly wrong and unhelpful.

Is there a way to fix this?