Learn well your grammar, / And never stammer,
Write well and neatly, / And sing most sweetly.
Drink tea, not coffee; / Never eat toffy.
Eat bread with butter. / Once more, don't stutter.
The mathematician Charles Dodgson, who indeed suffered from stammering, wrote those lines when he was 13, and they anticipate his later nonsense verse, such as:
'Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.