Formal:
* "My understanding surpasses my ability to express it." This conveys a sense of profound understanding.
* "Words fail to capture the full extent of my comprehension." This emphasizes the limitations of language.
Informal:
* "I get it, but I can't put it into words." This is a more casual way to express the same idea.
* "There's so much more I understand, but I don't know how to say it." This highlights the depth of your understanding.
Figurative:
* "My mind is teeming with ideas, but my tongue feels tied." This uses imagery to express the struggle to articulate your understanding.
* "The words are there, but they're just not coming out." This emphasizes the internal conflict between understanding and expression.
Ultimately, the best way to say it depends on the context and the tone you want to achieve.