Indefatigable comes from Latin indefatigabilis, formed from the prefix in- "not" plus defatigare "to tire out." Here the prefix de- means "entirely." You can remember the root fatigare because it sounds so much like the English fatigue.

What is the correct British pronunciation of indefatigable?

Break 'indefatigable' down into sounds: [IN] + [DI] + [FAT] + [I] + [GUH] + [BUHL] - say it out loud and exaggerate the sounds until you can consistently produce them.

What does loquacity mean?

: the quality or state of being very talkative.