👉 In linguistics, an isogloss (also known as a "diacritic" or "symbol") is a symbol that represents a sound in a language. It is used to indicate whether a word should be pronounced with a particular vowel or consonant position. For example, the English word "dog" has two isoglosses: /dɒg/ and /dɒɡ/. The first is an "a" sound, while the second is a "o" sound.
