For the record, Wikipedia states they are diacritics. I'm leaning toward agreeing due to this observation: "In most Latin-based orthographies, the lowercase letter i conventionally has its dot replaced when a diacritical mark atop the letter, such as a tilde or caron, is placed." Ex: aeiouyj, âêîôûyj, äëïöüÿj, áéíóúyj́ (oops, my example shows an accent above the J's tittle–down one, but three up)

https://en.wikipedia.org/wiki/Tittle