Comment by CMay

Would it be possible to have 3-4 words and you have to make sure that each word you produce results in a valid phrase? So not only the final phrase makes sense, but you have to navigate through a path of valid phrases.

This way you might remove a letter from different words and have to think ahead to decide if the result would remain coherent in order to avoid an error.

The computational complexity of identifying phrases that can be reduced like this while having a coherent path might increase rapidly.