The essential thing that needs to be understood in the title is the fact that the term “hearing-impaired” covers both hard-of-hearingness and deafness. Contrary to many articles and opinions, these two are not the same. Hard-of hearingness can be defined as hearing loss between 40 and 80 dB, whereas hearing loss exceeding 80 dB is defined as deafness. Others put the mark for hard-of-hearingness at 30 dB and for deafness at 90 or even 95 dB. The line between them is liquid, hence the problem in accurately describing a person as “deaf” or “hard-of-hearing”. A second factor would therefore be the person’s choice of first language – spoken mother language in the case of a hard-of-hearing person, or sign language in the case of the deaf.
Four different situations can be outlined and each of them will be presented separately.
The first is pre-lingual deafness, meaning the person described lost the ability to hear before the age of three. In most cases such a person is born deaf, although a slight percentage are results of illnesses. Most of children who are pre-lingually deaf learn to use sign language and become fluent speakers in it. In most cases their ability to learn spoken languages is hampered by their hearing loss, and even the hearing aids are not much of a help. A vast percentage of the pre-lingually deaf is composed of the children of deaf parents and therefore sign language is their first language. It is important to note that hearing loss does not hamper the capacity to learn sign language. Their language acquisition is therefore easy and natural, and they do not suffer from a language delay. It should be interesting to note that sign language using infants babble just as the hearing and speaking children do. The signs they make are incorrect and few. A minor amount of pre-lingually deaf children come from hearing families. Those are raised in a speaking environment and therefore their first language is usually the spoken one. Some parents and/or siblings learn sign language to communicate with such children, but in most such cases it will be the second language. The capacity of pre-lingually deaf to learn language is not hampered per se, but their language acquisition is often slower and occurs later than normal, which is called language delay. Its effects are often profound and most of such children do not ever acquire the level of spoken language mastery shown by their hearing peers. In addition, their speech is often flat and lacks intonation, or is abnormally loud or silent. Their acquisition of a spoken language is usually the effect of a hard work on the part of parents, teachers and specialists. As mentioned before, they are usually mono- or bi-lingual. Deafness prevents them from learning foreign languages the traditional way, but they can learn them with another approach (mostly visual based, of course).
The second case is pre-lingual hard-of-hearingness, which is defined as a hearing loss acquired in the first two years of life. The causes are the same as in the case of pre-lingually deaf. There is no apparent trend as to whether they are mostly children of deaf parents or hearing ones. As usual, the children of the deaf will learn sign language with little or no difficulty at all, where the rest will learn spoken language. Some of them are bilingual, though, and their fluency in the second language (spoken or sign, depending on the first one) is lesser than it could be. Nearly all of them use hearing aids nowadays, although the effect of their usage depends entirely on the individual and varies wildly. Children who amount to the speaking group often suffer from language delay. The quality of their speech depends on the severity of their hearing loss and the same can be said for their language acquisition. Language delay can be prevented (and the future level of language mastery improved greatly) by fitting a child early with hearing aids – ideally in the first six months of life. This fact went nearly unnoticed in Poland, even among the specialists, for a long time. Dr. Geremek was one of the audiologists in Poland to support early use of hearing aids in the hard-of-hearing children in the early nineties. One of the reasons for her breakthrough may be the fact that her daughter has a severe hearing loss, bordering on deafness. Nowadays all the infants are screened for possible hearing loss, which makes fast reaction possible. Some of them can even receive cochlear implants. Most of these can master the spoken mother language and learn another one later in life. Usually their language acquisition is limited to two spoken languages… but, exceptions do exist!
Thirdly, the post-lingual deafness can be defined as losing the ability to hear later in life (anytime from four years of age). It is usually caused by an illness (such as measles, meningitis), some medications (strong antibiotics, such as the ones used in treating [gruźlica]), or an accident. Most of these people come from speaking environment and therefore face serious challenges. While language delay is not an issue in most cases, early hearing loss can affect the spoken language acquisition nearly as much as in the case of pre-lingually deaf. Their first language is usually the spoken one, although individuals living in or close to Deaf communities learn sign language after becoming deaf themselves. The notes on speech of deaf people remain true in this case. Some of the post-lingually deaf receive cochlear implants. It has to be noted that retaining the ability to speak language is a very hard work for them. They lack auditory feedback and have to focus hard on making themselves understood. Being implanted or having hearing aids can make their spoken language acquisition easier, but again, it depends on the individual. Moreover, not all of them qualify for a cochlear implant. While they are often bilingual (spoken language and sign language) they usually do not learn any more languages. Exceptions do exist, again, of course.
The final case is post-lingual hard-of hearingness, which means hearing loss acquired from four years of age up. The causes are mostly the same as above, with the addition of long-term exposure to noise and age. The hearing loss caused by this is known as noise-induced. The loss caused by age affect high frequencies mostly and can be remedied effectively by hearing aids. This statement is usually true for other causes, too. It obviously does not impact language acquisition, unless it happened very early. Nor does it affect the level of language mastery. Nearly all of post-lingually hard-of-hearing use spoken language, since a vast majority comes from speaking communities. Many of them have already acquired a second or even a third spoken language in life and this language acquisition is not affected either, unless a person learns a new language after becoming hard-of-hearing.
The above cases have illustrated the situation clearly. Contrary to popular belief, deaf or hard-of-hearing people are not stupid nor is their capacity for first (or second, third and so on) language acquisition limited in any way. Deaf or hard-of-hearing children are excluded from learning a second foreign language at schools (the first being English), but they are not in any case prevented from learning foreign languages either.
Originally written for my university studies - I'm studying English and this was an interesting idea I had for my Language Studies.
Links to some materials I had gathered while working on this:
Warning! The last link is in Polish!