Hi Paul,

search for this line in templates/default/subtemplates/posting.tpl.inc:

<label for="captcha_code">{#captcha_expl_math#} {$captcha.number_1} + {$captcha.number_2} = </label><input id="captcha_code" type="text" name="captcha_code" value="" size="5" maxlength="5" /></p>

and replace it by

<label for="captcha_code">{#captcha_expl_math#} {$captcha.number_1|replace:"1":"one"|replace... ... ... ...} + {$captcha.number_2|replace:"1":"one"|replace... ... ... ...} = </label><input id="captcha_code" type="text" name="captcha_code" value="" size="5" maxlength="5" /></p>

Alex