private function getSuffixesToTry()
    {
        if ($this->suffixesToTry === null) {
            $this->suffixesToTry = [];

            if (isset($this->conf['salutation'])) {
                if ($this->conf['salutation'] === 'informal') {
                    $this->suffixesToTry[] = '_informal';
                }
                $this->suffixesToTry[] = '_formal';
            }
            $this->suffixesToTry[] = '';
        }

        return $this->suffixesToTry;
    }