The lowercase tokenizer, like the
letter tokenizer breaks text into terms
whenever it encounters a character which is not a letter, but it also
lowercases all terms.  It is functionally equivalent to the
letter tokenizer combined with the
lowercase token filter, but is more
efficient as it performs both steps in a single pass.
POST _analyze
{
  "tokenizer": "lowercase",
  "text": "The 2 QUICK Brown-Foxes jumped over the lazy dog's bone."
}The above sentence would produce the following terms:
[ the, quick, brown, foxes, jumped, over, the, lazy, dog, s, bone ]
The lowercase tokenizer is not configurable.