Speak, spake, spoken. Spricht, sprach, gesprochen. These are examples of ablaut, a type of vowel variation or apophony. Umlaut (e.g., “goose” and “geese”) and vowel length changes due to stress patterns (e.g., “photography” and “photograph”) are also examples of apophony. The family of words formed from the root sprechen – “to speak” – is larger and more varied in German than in English:
die Sprache – “language” and “speech”
sprachlos – “speechless”
der Lautsprecher – “the loud speaker”
die Absprache – “agreement”
das Gespräch, im Gespräch mit – “conversation, in conversation with”
die Besprechung – “meeting”
die Sprechstunde – “consultation” or “office hours”
das Sprichwort – “proverb, adage, saying”
der Anspruch – “claim”
der Einspruch – “objection” in the legal sense
der Widerspruch – “contradiction”
Although many of the English translations incorporate aspects from semantically related word families, for example, “to converse” and “to say” (you may also have noticed the “diction” inside the word “contradiction”), I find myself wondering if native speakers of German find the words on the list above to be more similar in meaning that do English speakers given the sound overlap. It is a feature of human, as opposed to other animal languages, that the connections between words and sounds are for the most part arbitrary (otherwise we couldn’t have “meeting” and Besprechung). However, it is also the case that there are some interesting sound-meaning relationships. See, for example, this Wikipedia article on how people consistently associate nonsense words with shapes: http://en.wikipedia.org/wiki/Bouba/kiki_effect and check out this piece on the SN connection: http://www.grammarphobia.com/blog/2007/03/a-nosy-question.html
Earthquake Words/Erdbeben Wörter 