In order for lexicon improvements to be easily included in later Speechoid releases, or integrated with Wikidata, it is important that they are released under CC0, independently of the default license on the wiki. There is precedence for this e.g. help namespace on mediawiki.org and structured data on Commons.
The license needs to be announced both on the Lexicon edit special page and, if implemented that way, the lexicon namespace (broken out to T280619).
Ideally the license is set by config, with CC0 as default.
This is to be implemented in the future LexiconLocalStorage that stores data as JSON in articles on the Wiki.