A hemiola is the articulation of two bars of triple time as if they were three bars in duple time.

Yes, you can. Normally 6-8 is two groups of three in a bar, but three crotchets gives a cross-rhythm called a hemiola.

Melisma: group of notes sung to a single syllable

Marilyn S. Brossard has written:

'A study of the musical significance of hemiola in selected piano works by Johannes Brahms' -- subject(s): Musical meter and rhythm

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 3 words with the pattern H----LA. That is, seven letter words with 1st letter H and 6th letter L and 7th letter A. In alphabetical order, they are:

harmala

hemiola

hexapla