The stressed syllable is spoken louder, and the rest of the word often has a falling intonation.

I must have spoken louder than I meant to.

Travis had spoken louder than he'd intended.

The players have said they don't want a work stoppage this time, and their actions have spoken louder than their words.

A word was audible, as if it was so important it had been spoken louder, extended: money.

He'd spoken louder and louder, until at the end he might almost have been addressing a crowd of thousands gathered in the Royal Square.

I had spoken louder than I meant.

John heard only the two words at the end, spoken louder as the rumblings of the armored car increased on a steepening climb.

The silence was broken with one muffled sentence that could not have spoken louder.

Also, as a friend of mine once observed, it is surprising how English becomes understood when spoken louder and louder.