It depends on the word. It sometimes adds a syllable but not always.
-ing-ed-est-er
The stressed syllable in "disappointed" is the second syllable, pronounced as "dis-a-POINT-ed."
The stressed syllable of "interested" is the second syllable - "es" in "in-ter-est-ed".
The stress syllable in "interested" is the second syllable, "ter." So it is pronounced as "IN-ter-est-ed."
Touched only has one syllable. The -ed sounds like an extra syllable.
-ing-ed-est-er
No. -ed makes it sound like an extra syllable but it isn't.
at-tend-ed
The stressed syllable in "disappointed" is the second syllable, pronounced as "dis-a-POINT-ed."
The stressed syllable of "interested" is the second syllable - "es" in "in-ter-est-ed".
"Played" has one syllable. The ending "-ed" has no vowel (even though it is written with one), so it does not add a syllable to "play". In words ending in "t" or "d", a vowel is added before this ending, so in those cases, you do wind up with an extra syllable.
The stress syllable in "interested" is the second syllable, "ter." So it is pronounced as "IN-ter-est-ed."
The word "short" can become "shorter" if you add a syllable to it.
weed-ed, two syllables. How you do that is you say the word to claps and every syllable is a clap.
Touched only has one syllable. The -ed sounds like an extra syllable.
sus pect ed
There isn't a final syllable in the word called. The word called is only one syllable. The -ed may make it sound like another syllable but it isn't.