Research has shown that being cut off from high frequency sounds may have a negative impact on speech perception in adults.
It is also clear that a high frequency hearing loss may result in a delay or failure of normal language development in children.
Being able to discriminate sounds in spoken language depends a great deal on the extent to which you have access to high frequency sounds. For many consonants, the spectral energy is primarily located in the high frequency region.
Phonemes such as /s/, /∫/, /t/, /z/ are therefore difficult to discriminate if you have a hearing loss in the high frequencies. In spoken English being able to discriminate /s/ and /z/ is important because these phonemes mark plurals, possessions and contractions as well as the third person singular tense.
Also being able to distinguish similar sounding words such as sip – tip –ship – chip and but – bus – bust will be impaired with high frequency hearing loss. This will also have an effect on language production in terms of proper pronunciation of for instance /s/ sounds in spoken language.