Best practices in accessibility are usually implemented, both on a technical and linguistic level, during the preliminary phases of the web development cycle. However, when a web site needs to be made multilingual, the transfer of textual accessibility becomes an imperative task during the localization (i.e. translation and adaptation) process. This research focuses on how localizers can obtain a degree of linguistic accessibility in the target-language web site comparable to that achieved in the source one, especially regarding text alternatives for visual content. Our ultimate goal is to develop a methodology through which expert and automated evaluation practices are merged by means of a controlled-language checker for Spanish and English web content.