Old English is one of the West Germanic languages, and its closest relatives are Old Frisian and Old Saxon. Like other old Germanic languages, it is very different from Modern English and difficult for Modern English speakers to understand without study. Old English grammar is quite similar to that of modern German: nouns, adjectives, pronouns, and verbs have many inflectional endings and forms, and word order is much freer. The oldest Old English inscriptions were written using a runic system, but from about the 9th century this was replaced by a version of the Latin alphabet.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What replaced runic writing in the 900's
unanswerable