private static function makeVerbMapping(array &$verb)
{
$imperative_neutral = 'なさい';
$gerund = 'ながら';
$polite = 'ます';
$volition_polite = 'ましょう';
$polite_past_neg = 'ませんでした';
$neg = 'ない';
$neg_past = 'なかった';
$factitive = 'せる';
$factitive_c = 'す';
if (!array_key_exists('base_fact', $verb)) {
$verb['base_fact'] = $verb['base_neg'];
}
if (!array_key_exists('base_passive', $verb)) {
$verb['base_passive'] = $verb['base_neg'];
}
if (!array_key_exists('imper_hard', $verb)) {
$verb['imper_hard'] = $verb['base_e'];
}
$verb['imperative_neutral'] = $verb['base_i'] . $imperative_neutral;
$verb['gerund'] = $verb['base_i'] . $gerund;
$verb['polite'] = $verb['base_i'] . $polite;
$verb['volition_polite'] = $verb['base_i'] . $volition_polite;
$verb['polite_past_neg'] = $verb['base_i'] . $polite_past_neg;
$verb['neg'] = $verb['base_neg'] . $neg;
$verb['neg_past'] = $verb['base_neg'] . $neg_past;
$verb['factitive'] = $verb['base_fact'] . $factitive;
$verb['factitive_c'] = $verb['base_fact'] . $factitive_c;
return $verb;
}