ahalik eta + -en

How to build it. Start with the superlative in -en and put ahalik eta in front of it:

• azkar → ahalik eta azkarren (as fast as possible)
• laster → ahalik eta lasterren (as soon as possible)
• asko → ahalik eta gehien (as much as possible)
• gutxi → ahalik eta gutxien (as little as possible)
• ondo → ahalik eta ondoen (as well as possible)

gehien is irregular: it is the superlative of asko, just as gehiago is its comparative. ondoen is regular (ondo + -en), and hobekien means the same.

Variants. eta can be dropped: ahalik azkarren. The form with the article is also correct, and Euskaltzaindia's handbook prefers it with adverbs in careful writing: ahalik eta azkarrena, ahalik eta ondoena.

With describing words. It can describe a noun too, with the article: parte-hartze ahalik eta zabalena (the widest possible participation). This is more common in writing.

Adverbs for actions. When you talk about how an action is done, use an adverb: ahalik eta ondoen irakurri (read as well as possible). The adjective form hoberen does not fit here.

In speech, people also say ahal den bezain azkar (as fast as it can be), built with bezain and ahal izan. For as soon as possible, you will also hear lehenbailehen.