The function appears to work correctly for most words, but there are some exceptions. For example, when the input is "a", the output is "a1" instead of "a". Additionally, when the input is "i", the output is "i1" instead of "i". It seems that the function has a problem with words that start with the letter "a" or "i".

Can you now write a description of the function that takes into account the exceptions you've observed?