For example, the HTML symbol "x̄" combines two codes — the base letter "x" plus a code for the line above (̄ or ¯).
fɔːɹ ɛɡzˈæmpəl, ðɪ ˌeɪtʃtˌiːˌɛmˈɛl sˈɪmbəl "ks" kəmbˈaɪnz tˈuː kˈoʊdz — ðə bˈeɪs lˈɛɾɚ "ˈɛks" plˈʌs ɐ kˈoʊd fɚðə lˈaɪn əbˌʌv mˈækɹɑːn ɔːɹ.