pspell_config_repl() should be used on a config before calling pspell_new_config(). The replacement pairs improve the quality of the spellchecker. When a word is misspelled, and a proper suggestion was not found in the list, pspell_store_replacement() can be used to store a replacement pair and then pspell_save_wordlist() to save the wordlist along with the replacement pairs. The file should be writable by whoever php runs as (e.g. nobody). Please, note that this function will not work unless you have pspell .11.2 and aspell .32.5 or later.
Example 1. pspell_config_repl()