why do we have a silent k in english
Silent k In Old English, ⟨k⟩ and ⟨g⟩ were not silent in these words. Cognates in other Germanic languages show that the ⟨k⟩ was probably a voiceless velar plosive in Proto-Germanic (compare German Knecht to knight, Knoten to knot, etc. where the initial ⟨k⟩ is not silent); likewise, ⟨g⟩ was probably a voiced velar plosive (compare German Gnom to gnome, Gneis to gneiss, etc. where the initial ⟨g⟩ is not silent).
Stress (linguistics) Some languages are described as having both primary stress and secondary stress. A syllable with secondary stress is stressed relative to unstressed syllables but not as strongly as a syllable with primary stress. As with primary stress, the position of secondary stress may be more or less predictable depending on language. In English, it is not fully predictable: the words organization and accumulation both have primary stress on the fourth syllable, but the secondary stress comes on the first syllable in the former word and on the second syllable in the latter. In some analyses, for example the one found in Chomsky and Halle's The Sound Pattern of English, English has been described as having four levels of stress: primary, secondary, tertiary, and quaternary, but the treatments often disagree with one another.