I'm trying to teach students how to say their names in Irish, and I have two students named Heather. I know the word for heather is "fraoch" but is that what would be used for a woman's name?
I'm also wondering about Margot.

I've never seen 'Fraoch' as a name for a person: It would seem odd, I'm sure, to a native speaker.

Quite a few names like this have become popular because they evoke the Irish (or Scottish) heritage in some way. Some go pretty far back -- 'Tara', a historic placename in Ireland, has been used by Irish Americans for generations.

This sort of thing is now found more often in Ireland (via Irish America?). For example, I met a young woman from Gaoth Dobhair, in the heart of the Irish-speaking areas of Donegal whose name is Tara. But she called herself that in both languages, ie, she did not translate it into Irish (Teamhair).

So I think Heather would be 'Heather'. But no harm in telling her that the plant is 'fraoch'.

Margot is probably related to Margaret and would be 'Mairéad'. But I'm sure there are Margot's in the Gaeltacht.

As the quote below shows (and thanks to someone whose name I lost -- I think this was in a posting on the Gaelic-L), there actually was a prominent character in Irish mythology whose name meant 'heather'. As you can see, however, the connotations are very different from the delicate, somewhat upper-middle class female name of today!

(I read recently, by the way, that some 12,000 given names occur through the Irish Texts of the Middle Ages. If true, most must have been unique to an individual or a very small number of people.)

Seo sliocht as [here is a passage from]'Gaelic Personal Names', le Donnchadh Ó Corráin agus
Fidelma Maguire: " Fráech: Fraoch (fréch). Derived from 'fráech'
'heather'. Fráech was the warrior slain in single combat by
Cúchullain.
As a surname it would be Ó Fraoigh (pronounced 'freeh' or 'freeg".
It could also be Mac Fraoigh.

I always forgot what that poor guy's name was and wasn't sure of the connection with heather anyway!

In the Irish/English dictionary the word SPIDEOG means robin, my friends name. BUT; can someone tell me how to pronounce it? Phonetically? Thanks

Here's a guess: Spid-jug.
I'm fairly new to Gaeilge, and have no native-speakers to learn from, save one who "was" fluent in her 20's (many years ago -- she asks me to translate for her, now)

Have you been learning Donegal Irish? It's fine as such except I would put the d with the j or drop it, lest it confuse some one. (It's only one consonant sound.)

In Connaught, further south, it would be SPIH-djoag (with a long 'o' sound). In Munster it would be closer to spih-DYOAG. Assuming they don't have their own version of 'spideog'.

Spideog Mhuire (robin of Mary, 'WIH-ruh') -- Robin red-breast.