They act as a "guide" for the reader, ensuring names like Zoë aren't mispronounced as "Zo".
why learned is not learnèd, and why no one uses noöne. : r/linguistics diacritic
Used in English primarily for poetic effect to show an extra syllable is pronounced, like learnèd . They act as a "guide" for the reader,
They distinguish words that look identical, like the verb resume (to start again) vs. the noun résumé (a CV). diacritic