Some letter forms derive from existing letters: The right-swinging tail, as in , indicates retroflex articulation. It originates from the hook of an r. The top hook, as in , indicates implosion. Several nasal consonants are based on the form : . and derive from ligatures of gn and ng, and is an ad hoc imitation of . Letters turned 180 degrees for suggestive shapes, such as from . Either the original letter may be reminiscent of the target sound, e.g., or the turned one, e.g., . Rotation was popular in the era of mechanical typesetting, as it had the advantage of not requiring the casting of special type for IPA symbols, much as the sorts had traditionally often pulled double duty for and , and , and , and to reduce cost. thumb|An example of a font that uses turned small-capital omega for the vowel letter ʊ. The symbol had originally been a small-capital . Among consonant letters, the small capital letters , and also in extIPA, indicate more guttural sounds than their base letters is a late exception. Among vowel letters, small capitals indicate lax vowels. Most of the original small-cap vowel letters have been modified into more distinctive shapese.g. from with only remaining as small capitals.
Some letter forms derive from existing letters: The right-swinging tail, as in , indicates retroflex articulation. It originates from the hook of an r. The top hook, as in , indicates implosion. Several nasal consonants are based on the form : . and derive from ligatures of gn and ng, and is an ad hoc imitation of . Letters turned 180 degrees for suggestive shapes, such as from . Either the original letter may be reminiscent of the. target sound, eg., or the turned one, e.g., . Rotation was popular in the era of mechanical typesetting, as it had the advantage of not requiring the casting of special type for IPA symbols, much as the sorts had traditionally often pulled double duty for and , and , and , and to reduce cost. thumb|An example of a font that uses turned small-capital omega for the vowel letter ʊ. The symbol had originally been a small-capital . Among consonant letters, the small capital letters , and also in extIPA, indicate more guttural sounds than their base letters is a late exception. Among vowel letters, small capitals indicate lax vowels. Most of the original small-cap vowel letters have been modified into more distinctive shapese.g. from with only remaining as small capitals.