When I speak English, it is often necessary to use the adverb or noun form of a certain word. However, even when it seems more suitable in a given situation or context, I don't use a prefix or suffix just because I'm not quite sure that it would be correct.

For example, the word conscious, I could use it in a variety of ways just by using some prefixes or suffixes like 'un', 'ness', or a combination of both. But I'm always wondering if a given form exists, so I'll google it, and most times it does.

My question is, is there any criteria I should use when placing suffixes and prefixes? I often say what sounds correct, but what if it doesn't? Would it sound too strange?

  • 1
    Yes, derivational affixes have lots of arbitrary requirements about what they'll attach to. Unfortunately, there's no simple set of rules you can memorize.
    – user230
    Apr 5, 2015 at 21:50

3 Answers 3


You didn't mention specific examples of words you have formed, so I can only answer generically. The answer is, yes and no.

Yes, because English has no formal governing body that dictates what is correct or incorrect. Rather, "correctness" is determined by consensus usage. Although there are dictionaries and grammar books, lexicographers and grammarians are supposed to document common usage, rather than make up arbitrary rules. Furthermore, English has a long tradition of accepting new compound words, stretching all the way back to the days of Beowulf. If your word successfully communicates your intent to the listener, then it has served its purpose. For example, the built-in spellchecker in Mac OS X highlights undoneness as not a word, but I would consider it a perfectly fine word to use (as in "I was uncomfortable with the undoneness of the hamburger"). There is a lot of tolerance for inventiveness, particularly in spoken English.

No, because there are limits to what words people like to use, and those limits are somewhat arbitrary and illogical. Why can someone be disgruntled, but not gruntled? Why is postpone a standard English word, but prepone is only common in Indian English? Why is it antidisestablishmentarianism, but not contraunetablishmentarianism?

There's a whole tag on english.stackexchange.com dedicated to this topic: [is-it-a-word]. That is, unfortunately, the simplest answer I can give.

  • I think you must be an exceptionally "tolerant" Anglophone! I think a reference to the undoneness of a burger/steak would be somewhat ridiculous. I can't imagine saying "Waiter! This steak is undone!" (sounds like facetiously mimicking Shakespearean usage to bewail the poor thing's fate! :). But since I could use underdone there, I suppose I could tolerate complaining about its underdoneness (as an overtly facetious usage) in certain contexts. Apr 5, 2015 at 12:51
  • Thanks a lot! That answers my question pretty well, now I feel more confident to use prefixes. I think that undoneness would sound a bit strange just because we normally don't need to describe the quality of being undone. Apr 5, 2015 at 17:46
  • I'd agree with @FumbleFingers that in my neck of the woods (eastern US), "undoneness" would probably get you strange looks, especially in the context of meat (where I'd expect "underdone" or "undercooked"). It's in the class of things where people could probably figure it out, but it'd be weird. So these things can be extremely region-specific.
    – cpast
    Apr 6, 2015 at 1:42

I would strongly advise OP (and any other learner) not to casually "invent" new words in this way.

In any given instance it's quite likely no-one will point out the unacceptableness1 of an incorrect formulation, particularly if the intended meaning is obvious. But if it passes unremarked, you'll naturally tend to think your "non-native speaker error" is in fact valid English. It's much easier to learn good habits/usage right from the start, rather than needing to "unlearn"2 bad habits first.

1 Almost every native speaker will reject this rare (now archaic) form in favour of unacceptability.
2 This usage is perfectly valid, but would often be placed in "scare quotes" because it's so rare.

  • Most of my doubts concerning the formulation of words arise when I have to say something that sounds perfectly fine, like 'doubtful', 'unnecessarily'. But I would certainly not say something like 'unlearn', nor would I 'unforget' instead of 'remember'. Apr 5, 2015 at 18:44
  • @hidekiEduardo: Unless you've actually heard the word doubtful, it's not obvious to me how you could say "it sounds perfectly fine", yet avoid using that method to come up with, say, questionful (which, although it appears in OED, wouldn't be considered "valid" by many if any native speakers). Again, most "ordinary" speakers would tend to class both unlearn and unforget as "invalid/non-standard", but the reality is both of them can be used in certain unusual contexts, even though only the former appears in OED. Forming "new" words using inflections is tricky. Apr 5, 2015 at 19:49
  • You're right, and as @snailboat said above, there's no simple set of rules we can memorize. We can do nothing but read a lot. The problem is that most of those words I would come up with when speaking or writing turn out to be actually correct when I do a research in a dictionary or google. So, those may be words that I subconsciously know bucause I may have read somewhere, but I'm not comfortable to use in a conversation because I'm not sure they exist. Apr 5, 2015 at 23:37
  • @hidekiEduardo: Do you perhaps have limited opportunities to engage in protracted conversations with native Anglophones? At 20, I could read French reasonably well (enough that I could concentrate on the content of a novel without being hampered by the language itself). Then I went to live in France for a year, and discovered that I was barely capable of having a conversation. Nothing changed for a couple of months, because I still spent quite a bit of time conversing with other Anglophones (and French students using me to practice English).... Apr 6, 2015 at 11:59
  • ...it wasn't until I spent a few weeks completely cut off from any English speakers that I quickly acquired the knack of conversing in French without fumbling for words. That's when you really get down to learning to generate utterances naturally - mostly repeating and rearranging the words you hear others using in speech, which isn't quite the same as what you read in literature, or find in the dictionary. Apr 6, 2015 at 12:04

My motto is, be courageous! Be adventurous! Ask people to let you know if you've made a mistake, or if they don't understand you.

My husband, an ELL, sometimes makes up words. He's come up with some good ones. For example, extrapolating from niceties, he made up tougheties, with the gh pronounced like an F.

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