The Semitic letter ×— () probably represented the voiceless pharyngeal fricative (IPA ). The form of the letter probably stood for a fence. The early Greek H stood for , but later on, this letter, ''eta'' (Η, η), became a long vowel, . (In Modern Greek, this phoneme has merged with , similar to the English development where EA and EE came to be both pronounced .) Etruscan and Latin had as a phoneme, but all Romance languages lost the sound — Romanian later re-borrowed the phoneme from its neighbouring Slavic languages, Spanish developed a secondary from F, then lost it again, and Castilian has developed an allophone in some Spanish-speaking countries. In German, ''h'' is typically used as a vowel lengthener, as well as the phoneme . This may be because was sometimes lost between vowels in German, but it may also have to do with the fact that Romance lost . Hence, H is used in many spelling systems in digraphs and trigraphs, such as ''ch'' in Spanish and English , French from , Italian , German .
Usage in English
Pronunciation
In most dialects of English, the name for the letter is pronounced and spelt 'aitch'[1] (or occasionally 'eitch'). Pronunciation (and hence spelling 'haitch') is usually considered to be h-adding and hence nonstandard. However it is standard in Hiberno-English. In Northern Ireland it is a shibboleth as Protestant schools teach ''aitch'' and Catholics ''haitch''.[1] The pronunciation affects the choice of indefinite article before initialisms beginning with H: for example "an HTML page" or "a HTML page". The pronunciation may be a hypercorrection formed by analogy with the names of the other letters of the alphabet, most of which include the sound they represent
Authorities disagree about the history of the letter's name. The The American Heritage Dictionary of the English Language derives it from French ''hache'' from Latin ''haca'' or ''hic'', from which it can be argued that the pronunciation is a result of h-dropping. The Oxford English Dictionary says the original name of the letter was ; this became in Latin, passed into English ''via'' Old French , and by Middle English was pronounced .
Value
H occurs as a single-letter grapheme (with value or silent) and in various digraphs, such as ''ch'' (, French , Greek and Italian ), ''gh'' (silent, , or ) , ''ph'' (Greek words with ), ''rh'' (Greek words with ), ''sh'' (), ''th'' (either like ''thin'' or like ''then''), ''wh'' (either , or : see wine-whine merger). In transcriptions of other writing systems, ''zh'' may occur (as in RussianDoctor Zhivago); this is generally pronounced in English, although this rendition is not necessarily faithful to the sound in the original language (as in the case of pinyin transcriptions).
H is silent in some words of Romance origin:
★ Initially in ''heir'', ''honest'', ''honour'', ''hour''; for American English usually also ''herb'', and sometimes ''homage''.
★ For some speakers, also in an initial unstressed syllable, as "an historic occasion"; to retain the "an" and pronounce the H may be considered affected.
★ After ''ex'' when x has value , as ''exhaust''.
★ For many speakers, after a stressed vowel and before an unstressed, as ''annihilate'', ''vehicle'' (but not ''vehicular'').
★ At the end of a word, as ''cheetah'', ''verandah''.
H is often silent in the weak form of some function words beginning with H, including ''had'', ''has'', ''have'', ''he'', ''her'', ''him'', ''his''.
In the German language, the name of the letter is pronounced .
In the German language, this letter is used in the digraph "ch" and the trigraph "sch" to indicate completely different sounds. Following a vowel, it often silently indicates that the vowel is long: In the word "erhöhen", only the first represents . This is the origin of the spelling (or pronunciation) of the English utterance "Eh?" which is not at all like an English pronunciation of the letter "e".
In 1901, there was a spelling reform which eliminated the silent in nearly all instances of
in native German words such as ''thun'' "to do" or ''Thür'' "door". It has been left unchanged in the word ''Thron'' "throne", which is spelled still in this way, also after the last German spelling reform.
In Unicode the capital H is codepoint U+0048 and the lowercase h is U+0068.
The ASCII code for capital H is 72 and for lowercase h is 104; or in binary 01001000 and 01101000, correspondingly.
The EBCDIC code for capital H is 200 and for lowercase h is 136.
The numeric character references in HTML and XML are "H" and "h" for upper and lower case respectively.
Hexadecimal
Some programming languages use "h" or "H" to mark Hexadecimal numbers. This can either be as a suffix, such as 05h, pronounced "five hex" or FFH "pronounced eff, eff, hex" or as a prefix, such as H'46' in Microchip MPASM assembly. However, there are also other standards that use different letters, such as "0x" in C.
In all of the above cases, it can also be described with the radix first, for example "hex forty-six", is the same as "forty-six hex".