When it is necessary to spell out words unambiguously over a connection with poor sound quality, the International Phonetic Alphabet will be found invaluable.

Ambrose
Ballyhoo
Chesterton
Dendrobium
Emphysema
Frankenstein
Gargle
Heliotrope
Ironic
Jehosaphat
Karma
Lysistrata
Mesembryanthemum
Nonentity
Oleomargarine
Punchinello
Querulous
Ranunculus
Salmagundi
Terpsichore
Ululation
Vercingetorix
Withlacoochee
Xanthippe
Youngstown
Zymurgy