breath, breathe, breadth

Breath or breath ( rhymes with death ) is a noun ( thing or idea ), meaning the air we inhale and exhale--
He had been running, and was out of breath.
It's so cold out that you can see your breath.

Breathe or breathe ( rhymes with seethe ) is a verb ( action word ), meaning to inhale or exhale air--
Open a window. I can hardly breathe in here.
He collapsed and couldn't breathe, so we called an ambulance.

Breadth or breadth ( bread-th ) is a noun ( thing or idea ), meaning width, or distance across--
"I love thee to the depth and breadth and height My soul can reach..."
Its breadth was nearly twenty feet.

Now that you know that, you can say--
"He was short of breath, and while he struggled to breathe, the breadth of his chest seemed to nearly double."

Note--the verb forms of "breathe" sound like "breathe"--
He is breathing better now.
It hurt every time he breathed.
When she breathes, she gets a pain in her side.
Note #2--"breaths" sounds like "breath", and means more than one "breath"--
She took little breaths of air, but still felt faint.
Note # 3--"breather" sounds like "breathe", and means a short break--
I think it's time for a breather.
Note # 4--"breathy" sounds like "breath", and describes a voice with a strong sound of air or breath in it--
She had a hoarse, breathy voice that got everyone's attention.
"Breathier" ( breath ee err ) describes a voice more "breathy" than another--
Her voice was breathy, but his was breathier.