Not a bad question really. I guess it can get confusing.

A dash (-) means I’ve been interrupted or stopped short on a word/sentence.

Three dots (…) means I’ve trailed off. The last sound didn’t stop, it faded out through a slowly closing mouth.

Combining the two (-…) indicates a sort of shock, the sound stopped, but the mouth movements finished the sound of the letter in question without any noise.

Tilide (~) indicates a held sound, usually going through extremely minor alternations in octave.

So, it’s not ‘Double like!’ shouted out flatly. It’s 'Double li~ke!’ with a sing-song inflection on the 'i’ vowel.