Foreign words to katakana conversion is based either on pronunciation or on spelling. It is not always possible to predict which of these is chosen as the basis for transcribing foreign words. If you see katakana words, the original foreign words can be guessed roughly based on the following rules.

A great number of katakana foreign words are used in Japan. Some Japanese companies also use katakana to write their names (e.g., ソニー (Sony), パナソニック (Panasonic), トヨタ (Toyota), etc.） for public use even though their official names may be written in kanji. Caution: The pronunciation of foreign words in katakana are completely "Japanized" and may sound very different from the original pronunciations from which the katakana foreign words are derived.

Innovative Writing Styles in Katakana

To approximate foreign language sounds more closely to the original sounds, the following katakana writing styles are optionally used. These writing styles require small vowel characters (ァィゥェォ as opposed to the normal size アイウエオ) in addition to small glide characters (ャュョ) and, infrequently, a small ヮ. Caution: Innovative writing normally applies only to katakana words. Do not try to apply these to hiragana words.