/s/ /z/ /iz/

[Belly T]

Could you give me the rule of pronouncing /s/ /z/ or /iz/ at the bold:
ex: dresses, plays, sandwhiches, witches, asks....

[Casiopea]

Could you give me the rule of pronouncing /s/ /z/ or /iz/ at the bold:
ex: dresses, plays, sandwhiches, witches, asks....

dress[Iz]
play[z]
sandwhich[Iz]
witch[Iz]
ask[s]

[Belly T]

That's just some examples, could you give me the rule/principal of pronouncing them?

[BobK]

Could you give me the rule of pronouncing /s/ /z/ or /iz/ at the bold:
ex: dresses, plays, sandw[h]iches, witches, asks....

Here's a first approximation:

if a plural (noun) or verb ending (/s/) follows a fricative or an affricate, use /ız/:
dress => /dresız/ ; witch => /wıʧız/; wedge => /weʤız, etc.

if a plural (noun) or verb ending (/s/) follows any other voiceless consonant, use /s/:
ask => /asks/ etc.

if a plural (noun) or verb ending (/s/) follows a vowel sound or a voiced consonant (that isn't a fricative or an affricate), use /z/:
play => /pleız/ ; weed => /wi:dz/ etc.

There must be a site somewhere that spells all this out. I'll have a look.

b

[rezaa]

- /s/ after voiceless sounds { p, f , th, t , k , h } except for [s, sh, ch] which are voiceless but they belong to another category called 'hissing sounds'

-/iz/ after the hissing sounds [s , z, sh , ch, 3 , d3]

-/z/ after all sounds saved the above.

[Belly T]

Thanks all
But I still don't get what is "fricative" or "affricative"?

[Noego]

Here's some definitions, I hope it helps:

Fricative
"A consonant, such as f or s in English, produced by the forcing of breath through a constricted passage. Also called spirant."

[Belly T]

And affricative?