Alliteration and assonance played a key role in structuring early Germanic, Norse and Old English forms of poetry. The alliterative patterns of early Germanic poetry interweave meter and alliteration as a key part of their structure, so that the metrical pattern determines when the listener expects instances of alliteration to occur.
Thus, the meter of a line may be described as being "iambic", but a full description of the rhythm would require noting where the language causes one to pause or accelerate and how the meter interacts with other elements of the language. Prosody also may be used more specifically to refer to the scanning of poetic lines to show meter.
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