Tin, lead and their alloys, due to their low melting temperatures and wide availability, are the most commonly used solder materials. In fact, lead has been used as a soldering metal for water pipes (also made of lead) even in Roman times, hence the scientific name for lead, Plumbum. Mechanical Properties.
hearing impairment - impairment of the sense of hearing. hearing disorder. disability, disablement, handicap, impairment - the condition of being unable to perform as a consequence of physical or mental unfitness; reading disability; hearing impairment. deafness, hearing loss - partial or complete loss of hearing.
Definition of Speech Impairment. A speech impairment is a condition in which the ability to produce speech sounds that are necessary to communicate with others is impaired. Speech impairments can be mild, such as occasionally mispronouncing a couple of words, to severe, such as not being able to produce speech sounds at all.