English has a few diminutive suffixes. Which one is used depends a lot on the shape of the word and the era, but the most common one today is -y.
So a child's toy might be Beary, and the kid might go by Johnny. We also have -ling, as in duckling, and a whole bunch of less common ones [0].
You're right, though, that we don't use our diminutives nearly as often as the Iberian languages do. If you tried to use them as much as you would in Portuguese you would definitely not sound like a native speaker, but they do exist.
Mostly they're used in the register of speech that we use when speaking to very young children (i.e. "baby talk"), in nicknames, or in older words that acquired a diminutive a long time ago and now register as just a word on their own.
So a child's toy might be Beary, and the kid might go by Johnny. We also have -ling, as in duckling, and a whole bunch of less common ones [0].
You're right, though, that we don't use our diminutives nearly as often as the Iberian languages do. If you tried to use them as much as you would in Portuguese you would definitely not sound like a native speaker, but they do exist.
Mostly they're used in the register of speech that we use when speaking to very young children (i.e. "baby talk"), in nicknames, or in older words that acquired a diminutive a long time ago and now register as just a word on their own.
[0] https://en.m.wiktionary.org/wiki/Category:English_diminutive...