If something is detectable I can detect it. If something is lovable I can love it. If something is delectable why can't I delect it? Any others?
Strictly speaking you can. Tenable derives from the Old French tenir: to hold. You can hold a tenable position...
Verb-able/ible does not always mean "capable/worthy of being verbed." Sometimes it means "capable of inducing noun/verb." Compare "pleasurable." And regarding "tenable," as Dywyddr points out, sometimes verb is in the original Latin, not English. Compare "risible," from Latin ridere, "to laugh," as in "deride/derision." Or "amicable" and "amiable," the former directly from Latin amicus, "friend," the latter via French ami. Which of course ultimately comes from amare, "to love."
If something is durable, why can't I dure it? Please Register or Log in to view the hidden image! Ok, I could possibly endure it though.. Here's hoping I didn't make a fool of myself Please Register or Log in to view the hidden image!
I'm not sure it is even theoretically possible that there would be a verb that wouldn't produce an adjective of the form verb+able/ible. Theoretically, all the adjectives that have the form verb+able/ible should also have the according verb, even if the verb may be somewhat different (e.g. endure, possibly due to an older distinction between transitive and intransitive verbs; or if the -able/ible adjective was loaned from Latin or French (e.g. amiable - if something is amiable, you can love it).
Yeah, but shouldn't it then have been: "If something is endurable, I can endure it" ? "Durable" doesn't mean the same as "endurable". Edit: "Ami" means "friend", doesn't it? In that case a literal 'translation' should be "befriendable" (which is, apparently, not a word.. :bugeyePlease Register or Log in to view the hidden image!.
You can make something durable (such as by coating an artifact with protective paint), so that it can endure the test of time. And yes, if something is endurable, then you can endure it.
Yeah, well, you can make something delectable as well.. Please Register or Log in to view the hidden image!
According to http://dictionary.reference.com/browse/amiable, amiable and amicable are comparable. Befriendable isn't a word because we already have amiable and amicable. Surely Facebook can change that too.
Exactly what he laid out in the OP. But perhaps I'm missing the point a bit as English is not my native language..
This is how I understand some patterns here: If something is detectable I can detect it. If something is lovable I can love it. If something is protectable I can protect it. If something is delectable I can (take) delight in it. If something is pleasurable I can take pleasure in it. If something is endurable I have made it (such that it can) endure. If something is profitable I have made it (such that it) brings profit. If something is delectable I have made it (such that it) brings delight.