I was born in Paris, but lived in the Southwest, near Bordeaux in an Italian community that spoke a Neapolitan dialect with a bit of Sicilian and Corsican thrown in. At school our prof was only interested in Shakespeare so when I came to England at the age of 19, well guess what? I could not understand the people around me.
Anyway, determination and utter focussing on my pronunciation (hours in front of the mirror having composed sentences with th) and years later I finally went into nursing. However, it became apparent that something in the way that I spoke was rubbing people’s back up the wrong way. After some illuminating points from my colleagues, I had to change the intonation on some words as I sounded harsh; an intense awareness on my pronunciation got me there. It was the tone in which I said for example: No! I don’t think so. In an English intonation the ‘no’ is soften by elongating it a bit ‘no-o’, and ‘I don’t think so’ both ‘I’ and ‘so’ are lowered in tone so to soften it up.
After many years here, and in some companies the questions about having an accent are interesting: am I Welsh? Scottish? Scandinavian? Or even Dutch. Not one bit of French or Italian!
Interestingly, after lacking contact with the French language for a while, I had to work on my intonation to help me sound French again. Oh! I almost forgot, I have also been told I have a southern English accent; cant hear that!