Full disclosure, I worked briefly with Ello / Catalin some years back.
They've done a lot of work on at least two dimensions: (1) handling the nonstandard sounds and habits of speech of very early readers, who might be as young as four, and (2) connecting this to a specialized teaching system based on the science of reading, e.g. decodable readers.
They've done a lot of work on at least two dimensions: (1) handling the nonstandard sounds and habits of speech of very early readers, who might be as young as four, and (2) connecting this to a specialized teaching system based on the science of reading, e.g. decodable readers.