If you cannot hear what people saying (or they cannot hear you), try “code-switching”. We identified six codes:
High English: your normal educated speech, with most vocabulary derived from French or Latin, e.g. “prospective students should board the transport provided to campus”.
Low English: you normal speech in the family, pub or sports terrace, with mostly Germanic vocabulary. The above sentence becomes “if you’re on the tour, get the bus to uni”.
Get phrases: the auxiliary “get” plus an adjective or participle; it may come from the absorption of Danes in the 11th century, and is often vulgar
Mime: you may recognise more than hundred mimes, but have not put them together as a lexicon. BSL provides a standard vocabulary, though some are not intuitive e.g. “what?”
Text: the numerals 0 – 9 are recognised everywhere, even where there is a local alternative e.g. Arabic, Chinese. The 26 Roman letter alphabet (in upper case) will also be recognised in nearly every country from brand names, e.g. MAZDA, MICHELIN, AK47, CRUISER, SAMSUNG
Viseme. This is what we can see on another’s lips – a “visible phoneme”.
There are additional part codes. Surgeons use a Graeco-Latin lexicon, of which lay people learn those that affect them. Motherese are reduplicated syllables parents everywhere acquire from the infant’s babble. Stress may sometimes be preserved when lexicon is lost. Pointing may help, but needs mime to disambiguate. Holding up six coloured pens and deliberately choosing one shows that you mean the attribute colour. Closed questions are used when your lexicon is small.
Lip reading
Most of us lose some hearing the 70s. The basic workaround is to move to a low-noise environment and place yourself so that your mouth can be seen. A room with no TV and low traffic noise, with two seats about two metres apart is near optimum. If you do a self-test such as https://www.lipreading.org/ you may be surprised to find that you score fairly well, despite no training. If you think about it, your first experience of language was watching mother’s mouth, before you could make out the sounds.
There are about 14 such “visemes”. The graphic below shows the five easiest vowels. Lip-reading can distinguish the front vowels of six wh* question words. The back vowels in “rain, snow, hail, slush” are much harder to see.
The graphic also shows the three easiest consonants. Every infant’s first words include “mom”, “nan” and “bab”. The is only one consonant viseme in these three words. An infant born deaf will have to distinguish them by the vowel. Hearing loss in later life is typically greater at high frequencies, so that “ss” and “sh” are lost first. English speech has 20 vowel and 24 consonant phonemes. The hearing-impaired infant or adult has to use other cues to differentiate 14 visemes into 44 phonemes.
Parents are delighted by the infant’s babble when a consonant and vowel come out together. As “m” and “ŭ” are usually first, “mŭmŭ” is viewed as “baby’s first word”, which parents repeat as “mama”. Over the next few months other sounds are shaped by parents into “motherese”. “baba” usually follows soon, which mothers is most language treat as “father”, with English being a little different. This is surprisingly similar in every language. The graphic below shows the motherese of Mandarin.
To conclude, hearing impairment involves requires ging back to seeing speech to work around some missing sounds.