I have dyslexia, and when I pronounce words in my head the syllable count and stress doesn't reflect the way the words are pronounced in everyday speech. I think you might describe it as phonetic pronounciation?
For instance, the IPA pronunciation for 'Strength':
/stɹɛŋkθ/, [st̠͡ɹ̠ɛŋkθ], [st̠͡ɹ̠ɛn̪θ]
However I found when I was trying to work out the syllables for this word, I would say (in my head) the word how I learnt to spell it:
stʌ•ɹ̠ɛn•gʌ•θʌ
Which is ~4 syllables, but when I speak the words out loud as part of a line of poetry (with the standard pronunciation) I can't for the life of me hear where the stress falls.
As an example, I tried to write this limerick for a puzzle:
These strings of digits are unique
My first in time and space so to speak
And so, you'll find, is my second
with three 'n' five names are reckoned,
And fourth's the random assignment technique
However I got feedback that it didn't scan, I figured out that my struggles were with the in-head/out-loud pronunciation I described above.
This is the 'fixed' version:
These many strings of digits unique
First made from space and time so to speak
The same for my second
Three 'n' five: names reckoned,
And my fourth has a random technique
But now this version doesn't quite sound right to me either.
Is there a way for me to check the meter, syllables and stress for writing poetry without relying on my (faulty) pronounciation?