Fill in the gaps in the following conclusion: “…phonological analysis of articulatory features of English vowels allows us to consider the following two characteristics functionally relevant:
a)_____ b)_____. The rest of the features mentioned above, that is ____, ____, and ____ are indispensable constituents of vowel quality.”

phonological analysis of articulatory features of English vowels allows us to consider the following two characteristics functionally relevant:

a) stability of articulation, b) tongue position.

The rest of the features mentioned above, that is lip position, character of vowel end, length, and tenseness are indispensable constituents of vowel quality.”