The spelling of "didst thing" can be confusing. "Didst" is the archaic second person singular past tense of "do" and is pronounced /dɪdst/. "Thing" is a common word that means an object, situation or action and is pronounced as /θɪŋ/. Together, "didst thing" means "you did something" in an older style of English. While the spelling may be unfamiliar to modern speakers, it highlights the evolution and diversity of the English language over time.