The implementation maintains a cache of stemmers for each thread that accesses snowball/3, providing high-perfomance and thread-safety without locking.

Arguments:

Algorithm	- is the (english) name for desired algorithm or an 2 or 3 letter ISO 639 language code.
Input	- is the word to be stemmed. It is either an atom, string or list of chars/codes. The library accepts Unicode characters. Input must be lowercase. See downcase_atom/2.

Errors

- domain_error(snowball_algorithm, Algorithm)

- type_error(atom, Algorithm)

- type_error(text, Input)