As you use Phonology Assistant (PA), it is important to understand the difference between phonetic characters (sometimes referred to simply as characters) and phones.
In PA, the phonetic characters consist primarily of the International Phonetic Alphabet (IPA) in the Unicode character encoding. PA includes some non-IPA characters in the standard inventory.
A phone is a speech sound. One or more phonetic characters represent each phone.
A base character is a phonetic character that can represent a phone. For example, o is a base character, because it represents the phone [o].
If a phonetic character cannot represent a phone by itself, it is not a base character. For example, over-striking tilde is not a base character. Two phonetic characters, base character o and diacritic character over-striking tilde, represent the phone [õ].
Most phones are represented by a single base character followed by zero or more modifying characters (diacritics or tone markings). For example, [o] or [õ].
However, some phones are represented by sequences that do not begin with a base character or that include more than one base character.
In phonetic transcriptions, PA assumes, as a rule, that each base character represents the beginning of a phone, with the following exceptions:
Before PA applies the general rule to a transcription, it considers any ambiguous sequences that you define to represent phones.
For example, if you define ts as the phone [ts], the base character s does not represent the beginning of a phone when it follows t.
If a word begins with a non-base character, PA assumes it is part of the representation of the first phone.
For example, if a word begins with ⁿd, the first phone is [ⁿd]. The base character d does not represent the beginning of a phone in that context.
If a transcription contains the upper or lower tie-bar character (Unicode character values U+0361 or U+035C, respectively), the two base characters surrounding the tie-bar, and any modifying characters on either side, represent one phone.
For example, t͡s or t͜s represent the phone [ts]. The base character s does not represent the beginning of a phone in that context.