#translatewiki.net a localisation has to be better than 50% before it is considered as a language for a localised WikiReader user interface. There are 66 languages that meet this criteria, there are 44 languages completely localised.
The question "where can I find WikiReader support for Tagalog" is a fair one. I cannot find it among the languages that are supported. Tagalog is fully localised.
One reason why there may be a delay between getting the localisation done and it being implemented may be found on the WikiReader developer blog; input methods.
There are several languages waiting for support that have another script. What will be of value is communications from WikiReader informing us of the status of all the languages waiting in the wings.