As can be seen in my audigram (PS form) (PDF form) (plot of hearing accuity--to hear speech, the two plotted lines must go all the way across the dotted box; to hear vowels and consonants, the two plotted lines must be above the contours labelled ``vowels'' and ``consonants''), I am nearly deaf. I depend on lip reading to understand spoken language. English is my native language and I lip read it very well, to the extent that occasionally, people even forget that I cannot hear.
Even though I speak Hebrew fairly well and am able to lecture on computer science in it and can read printed Hebrew (at one tenth the speed of English, because I must read each letter), I am totally unable to understand spoken Hebrew. Since my arrival to Israel as an immigrant in 1987, my ability to read lips in Hebrew has not gone up, despite three years of private lessons with a speech therapist. After those three frustrating years, I consulted some experts on teaching lip reading and they said that it is impossible to learn to read lips in any language but one's native after the age of five. Since I am a bit older than five, I stopped trying to understand spoken Hebrew. I find that if I speak Hebrew as well as I can, people answer me in Hebrew, and I cannot understand what they say. Therefore, I speak only English to encourage English replies.
My inability to understand spoken Hebrew was a major factor in my deciding to move from Israel to English-speaking Canada. Interestingly, when I first arrived in Canada, some thought I was Israeli (given my 11 years in Israel) and were really impressed with my very native-sounding English and my command of the North American slang! Eventually, I did enlighten them as to the true origin of my English.
The exact same situation exists with the other non-English languages that I know, French, German, Italian, Portuguese, and Spanish. I cannot understand them spoken either even though I speak them and read them (at about one half the speed of English (because the alphabet is more familiar to my English eyes)).
The best way to communicate with me is face to face. If that is not possible, then use e-mail or fax. Use the ordinary telephone as a last resort (at least until we get picture phones). Cellular phones, answering machines, voice mail, programmable phone calls, etc. are all disasters!
You can read a paper titled ``Requirements for Maintaining Web Access for Hearing-Impaired Individuals'' (in PDF form) (in PS.Z form) (in TXT form) which has an appendix with more details about my hearing. Also it's a good survey of how to kep the WWW accessible to the hearing impaired while making it more accessible to the sight impaired.