Completely agree. My story is almost exactly the same. Learning enough to speak the language is hugely important and it's one of the reasons, I believe anyway, that my cofounder and I have such a great relationship. I'm mostly hustle--worrying about marketing and having the right relationships, but I can code a mockup in fairly short order when it's needed. I might consider re-naming it "if you're not a technical cofounder then learn to speak the language."