The grapheme has been derived from the Greek word gr?ph?, and it is a fundamental unit in a written language. Graphemes are included in Chinese characters, alphabetic letters, numerical digits, punctuation marks, and the individual symbols of any genre of the world’s writing systems. A grapheme is stay in contact to one phoneme, but it is too much above the exception. When two graphemes are used for an individual phoneme it is called as graphs and three graphemes are used for singles is also known as trigraphs.
On the contrary, the single or individual grapheme can be represented multiple phonemes. If you want know more about grapheme then you should search the English phonemes. When you get the English phonemes, you can easily understand the best requirements to use the grapheme as per your needs. A single grapheme can be treated as individual unit for the purposes of collation properly. Moreover, the particular grapheme will represent various phonemes on occasions. For example in English sound /f/ is represented by ‘f’, ‘F’, ‘FF’, ‘ff’, ‘Ph’, ‘PH’, ‘ph’, ‘GH’, ‘gh’, as well as in a few place names of the Welsh origin by the ‘Ff’; whereas grapheme ‘f’ will as well represent phoneme /v/ (like in word of). In the script like Japanese katakana grapheme corresponds to the syllable (and more technically mora).
In a few languages, group of more than a grapheme is treated as the single unit for purposes of the collation, example in the Hungarian dictionary, and words beginning in cs come other words starting c, whereas in the Welsh dictionary, and words starting may come after other words starting by l. Besides, single grapheme in the print might not correspond to a single grapheme in the handwriting, example in the old German handwriting combination ch is generally written very differently from the c + h: given it has the own sound value, and there is the strong argument to treat treating this as single distinct grapheme.