It's interesting that the same consonants "כלב" are pronounced like "kelev" in the singular but "klav" in the plural.
that happends a lot in hebrew. as known in hebrew we're using niqqud-an alternative system of diacritical signs used to represent vowels or distinguish between alternative pronunciations of letters. depending on the phone (vowel or consonant), syllable (open or closed unstressed or not) and what kind of morpheme and grammatical conjugation, the words from the same semitic root sounds a bit different.
(For the record though: cats, unless it’s a samoyed or something.)
Ha, I heard that as חתולים אוכל בים and thought it had something to do with cats eating!