degrees of divergence from standard ASL in those imported ASL varieties. Bolivian Sign Language is reported to be a dialect of ASL, no more divergent than other acknowledged dialects. On the other hand, it is also known that some imported ASL varieties have diverged to the extent of being separate languages. For example, Malaysian Sign Language, which has ASL origins, is no longer mutually comprehensible with ASL and must be considered its own language. For some imported ASL varieties, such as those used in West Africa, it is still an open question how similar they are to American ASL. When communicating with hearing English speakers, ASL-speakers often use what is commonly called Pidgin Signed English (PSE) or 'contact signing', a blend of English structure with ASL vocabulary. Various types of PSE exist, ranging from highly English-influenced PSE (practically relexified English) to PSE which is quite close to ASL lexically and grammatically, but may alter some subtle features of ASL grammar. Fingerspelling may be used more often in PSE than it is normally used in ASL. There have been some constructed sign languages, known as Manually Coded English (MCE), which match English grammar exactly and simply replace spoken words with signs; those systems are not considered to be varieties of ASL. Tactile ASL (TASL) is a variety of ASL used throughout the United States by and with the deaf-blind. It is particularly common among those with Usher's syndrome. It results in deafness from birth followed by loss of vision later in life; consequently, those with Usher's syndrome often grow up in the Deaf community using ASL, and later transition to TASL. TASL differs from ASL in that signs are produced by touching the palms, and there are some grammatical differences from standard ASL in order to compensate for the lack of nonmanual signing. ASL changes over time and from generation to generation. The sign for telephone has changed as the shape of phones and the manner of holding them have changed. The development of telephones with screens has also changed ASL, encouraging the use of signs that can be seen on small screens. Stigma In 2013, the White House published a response to a petition that gained over 37,000 signatures to officially recognize American Sign Language as a community language and a language of instruction in schools. The response is titled "there shouldn't be any stigma about American Sign Language" and