The earliest weaving turns out not to be linen but nettle fibers and treated correctly. They have no sting and can be worked to be as soft as can be. Like linen, garments made from them can be a bit scratchy at first but not from nettle stings; they tend to be stiff like linen but warn for a time and washed several times, they can get butter soft. The Ancient Mesopotamians used to make the royal slaves wear the King's linen garments to get them soft for him before they touched his delicate skin.
Nettles are treated the same as flax and retted (rotted) either in a pond, the morning dew in Old Ireland (for an entire year or so), or sometimes a river. This removes the stinging part and leaves the core, which is hackled (beaten) to get the small fibers out and then "dressed" onto special spindles or made into one-way facing bundles for spinning.
In the Spring, the early plants don't sting, and Nettle soups are very good and probably kept a lot of Irish peasants alive during the era when their main diet was potatoes.