The two chief types are voiced and voiceless phonation. The adjectives 'voiced' and 'voiceless' seem straightforward, but one has to be careful when applying them to sounds. A sound can be called voiced if the vocal folds vibrate during much or all of its articulation, e.g. vowels such as /æ, iː, ʊ/ and voiceless if the vocal folds are pulled apart (i.e. abducted = they cannot vibrate), e.g. for consonants such as /s, f, θ/. The distinction between /z/ and /s/ is clearly one of voicing: either the vocal folds vibrate (= /z/) or they don't (= /s/).
Is this the only difference between /s/ and /z/? And what about pairs such as /p-b, t-d, k-g, f-v/?
For /s/ the friction is stronger and the duration greater than for /z/ (the same goes for /f-v/). See the sound traces for the two words 'Sue' and 'zoo':
For /p/ the closure is longer and the aspiration is usually stronger and longer than for /b/ (the same applies to /t-d, k-g/). And, last but not least, the muscular energy or tension needed to produce /p/ or /s/ seems to be greater than for /b/ or /z/. Occasionally there is no vocal fold vibration at all when you articulate /b/ or /z/, e.g. in words like 'lab' or 'lose'.
This is the reason why some phoneticians prefer the terms fortis (for /p, s/ etc.) and lenis (for /b, z/ etc.). So, when you try to make a distinction between word pairs such as 'feet-feed, lap-lab, loose-lose, tale-dale, peas-bees' and many others, don't concentrate too much on the vibrations of the vocal folds.(I can't dwell here on what you should focus on instead.)
The minor type of phonation is whisper phonation. /kə̣ṇ jʊ̣ hɪ̣ə̣ ṃị/.The dot is used as a diacritic to indicate whisper phonation.
Other types of phonation - breath phonation, creaky voice or falsetto - need not be discussed here.
The next blog entry in this series will deal with segmental articulation.