The first parameter of infl

Are you sure it's allowed to leave out the language on {{infl}}? It seems to me that it's never supposed to happen that way, and it's an error if it is. What use would the template be in any case, if the language is left out?

To display the inflection line? Some people use '''{{PAGENAME}}''', but a simple {{infl}} is also sometimes used. (I personally think that it's better to use infl than the alternative.)

I think that's better too, but I've always added the language as well. I'm not really sure what script to use if the language is not specified, though.

The first parameter could only be left blank if the language is English, otherwise the surrounding element wouldn't have the lang parameter set. {{{{{1|en}}}/script}} would probably work.

That would work if people are typing {{infl}}, but does anyone ever type (say) {{infl||verb forms}}? (I wouldn't have thought so, but I wouldn't have thought anyone just typed {{infl}}, either . . .)

I doubt anyone would leave {1} blank but specify {2}.