Spells per Day: At 2nd and 3rd level, a human paragon gains new spells per day (and spells known, if applicable) as if he had also gained a level in a spellcasting class he belonged to before adding the level. He does not, however, gain any other benefit a character of that class would have gained (bonus metamagic or item creation feats, bard or assassin abilities, and so on). This essentially means that he adds the level of human paragon to the level in the spellcasting class, then determines spells per day, spells known, and caster level accordingly.
If a character had more than one spellcasting class before he became a human paragon, he must decide to which class he adds each level of human paragon. If a human paragon has no levels in a spellcasting class, this class feature has no effect.