Mon-till-yay which comes across as pretty french sounding to me. At 3 syllables, you'll probably get the hang of it pretty quickly I think. Of course, depending on where you grew up maybe you're just not used to using some phonemes.
'et' often makes an 'ay' sound. I mean, the french word for 'and' is actually 'et' and it's pronounced 'ay.'
Another common one in French is -er and -ez to make the 'ay' sound. I think this is similar in languages like Spanish and maybe Italian as well, though I don't know.
French, Spanish and Italian all have a common root in Latin, so there are quite a few similarities between them.
Fun fact, I thought the last syllable in Montilyet would be pronounced more like 'yeah' than 'yay'. Both are possible, but the former would be more common for the ending of a word in French. Words like muguet, banquet, carnet, etc. The last syllable is an -eah as in 'yeah'. Oh well, end of lecture.
(native French speaker who teaches French as a second language)