For many deaf people and people with hearing impairments, subtitles are likely to be an important format for receiving information. Subtitling is text on screen representing speech and sound effects that may not be audible to people with hearing impairments. It is synchronised as closely as possible to the sound. People using subtitling range from those who have been profoundly deaf since birth to those who have become hard of hearing in later life. Viewers with a mild to moderate hearing loss are likely to rely on subtitles to aid their hearing rather than as a substitute. Subtitle users reflect the full range of proficiency in English. Some profoundly deaf people regard British Sign Language as their first language and are less fluent in written English. All of the groups mentioned above are likely, to a greater or lesser extent, to lip-read. Many people with good hearing also use subtitles so that they can watch television with the sound muted, for example so that they can simultaneously talk on the telephone or to learn English.