* Proto-Indo-European: The word's root is believed to be the Proto-Indo-European word "*lēgʰ-*," meaning "to speak, to gather, to read, to say."
* Latin: This word evolved into the Latin "littera," meaning "letter of the alphabet, inscription, writing."
* Old English: From Latin, it entered Old English as "lættere," which ultimately gave us the modern English word "letter."
Therefore, the word "letter" essentially means a "mark or symbol used for writing, representing a sound or sounds," with its origins deeply rooted in the concept of spoken language.
It's interesting to note that the word "letter" has retained its connection to the original idea of communication through speech, even as writing has evolved and become more complex.