 Re: how to pronounce?
We pronounce it as /0kæ tə 1klɪz əm/ in IPA.
Main stress occurs on the 1st syllable; secondary stress is on the 3rd. The consonant “c” after “a” is uttered as a hard sound, i.e. /k/ which usually is the phonics rule. The 1st vowel “a” is the ash “æ” (the short sound of “a”). The 2nd “a” in the 2nd syllable is reduced to a schwa “ə” after “t”. The “l” blend “cl” is pronounced as /kl/. The “y” in the 3rd syllable is uttered as a short “i” (/ɪ/) in a closed syllable and the sibilant “s” is usually voiced in “sm”(/z/). The “m” may be syllabic or uttered with a schwa in front of it /əm/. | 
Linear Mode
