The
micrea- part should be similar for most dialects but the
tonn part may vary (if native speakers bother to use this makey-uppey word at all.

)
.
.micrea-MICK-rhuh
/'m´ik´r´ə-/
The rest of the word will depend on how you pronounce
tonn "wave".
The "standardised"
lárchanúint (LC) pronunciation of
tonn and its plural
tonnta would be:
.
.tonn (LC) "wave"
TONN
/toN/
.
.tonnta (LC) "waves"
TONN-tuh
/toNtə/
For the full compound in a
lárchanúint pronunciation:
.
.micreathonn (LC) "microwave"
MICK-rhuh-HON
/'m´ik´r´əˌhoN/
.
.micreathoinne (LC) "of a microwave"
MICK-rhuh-HON-yih
/'m´ik´r´əˌhoN´ə/
.
.micreathonnta (LC) "microwaves"
MICK-rhuh-HON-tuh
/'m´ik´r´əˌhoNtə/
@Saoirse - I hope you realise this is a term from particle physics and not the name for the kitchen appliance. That is
oigheann micreathonnach "a microwave oven". Or did you get caught speeding (
brath micreathonnach feithicle "microwave vehicle detection")?
CONNEMARA PRONUNCIATION
(If you are only interested in standard Irish, don't read any further)
The Connemara pronunciation for
tonn and
tonnta is:
.
.tonn (GC) "wave"
TOON
/tu:N/
.
.tonnta (GC) "waves"
TOON-tuh
/tu:Ntə/
An older speaker of Connemara Irish might pronounce them:
.
.micreathonn (GC) "microwave"
MICK-rhuh-HOON
/'m´ik´r´əˌhu:N/
.
.micreathoinne (GC) "of a microwave"
MICK-rhuh-HWEEN-yih
/'m´ik´r´əˌhi:N´ə/
.
.micreathonnta (GC) "of microwaves"
MICK-rhuh-HOON-tuh
/'m´ik´r´əˌhu:Ntə/
Some Connemara speakers pronounce the word
tonnta as
tonntaí:
.
.tonntaí (GC)/TOON-twee
/tu:Nti:/
They might pronounce the word
micreathonnta as
micreathonntaí:
.
.micreathonntaí (GC)MICK-rhuh-HOON-twee
/'m´ik´r´əˌhu:Nti:/
(Posted for all you budding particle physicists from Connemara.

)