Adverbs versus Adverbs

TLDR: The word real is a modifier which like very works as an intensifier. Just like very, real can function not only as an adjective but also as a special kind of “adverb”.

As an adverb, it can only intensify other modifiers: it does not intensify verbs.

To compare real with very, consider how the very girl you were looking for might be very sweet-smelling, but you cannot *very look for her even if she is a real nice girl.

Real shares those properties, properties that are outside the stuffy eight-sided box of traditional part-of-speech tags some ‘grammarians’ believe we inherited from Latin.

A rose by any other name. . . .

First, here are some examples of sentences that discuss the fine fragrance of your sister’s rose:

1. Your sister’s rose smells real good. (arguably casual or informal)
2. Your sister’s rose smells really good. (unassailably fine)
3. *Your sister’s rose real smells good. (not grammatical)
4. Your sister’s rose really smells good. (again, a delightful aroma)
5. Your sister’s rose really smells well. (grammatical but nonsensical)

The lovely blossom does not work quite the way your lovely sister Rose does:

1. Your sister Rose smells real good. (arguably casual or informal)
2. Your sister Rose smells really good. (her fragrance is wonderful)
3. *Your sister Rose real smells good. (not grammatical)
4. Your sister Rose really smells good. (they might name a perfume after her)

5. Your sister Rose smells real well. (arguably casual or informal)
6. Your sister Rose smells really well. (her olfactory powers are excellent)
7. *Your sister Rose real smells well. (not grammatical)
8. Your sister Rose really smells well. (this is about her olfactory powers again)

Whatever you want to call real, it does not fit into neat and tidy categories. See also the question What’s an adverb?

The ‑ly and ‑like derivational suffixes

The ‑ly suffix is used to derive new modifiers from existing substantives (here read nouns), adjectives, or even at times verbs. That suffix has historically experienced a wide number of spellings, but the one that will be most familiar to English-speaking monoglots will be ‑like.

If you happen to know some German, then the cognate ‑lich will be a familiar suffix for you. All Germanic languages work this way: not just German but also Gothic, Dutch, and the various Scandinavian tongues. Sometimes these are a bit tough to track down the origins of without a good dictionary. For example, words like seem, seemly, unseemly come from Old Norse.

Something that complicates this is that the OED recognizes two different ‑ly suffixes.

1. one for making adjectives — call it ‑ly¹
2. the other for making adverbs — call it ‑ly²

However, their history is somewhat muddled and clearly interrelated.

Indeed, it is not always clear whether the derivation is from a substantive or an adjective. As you yourself mention with the case of ugly, sometimes the original base form did not survive, or did so in another way which we no longer readily recognize. But it’s still there. (Oh, and especial is not non-existent; just a bit old-fashioned.)

Here are some examples of modifiers with ‑ly at the end that may not leave a recognizable base in modern English.

• Silly is from seely, cognate to German selig and Dutch zalig.
• Only is from one-ly, and this is true whether used as an adjective or an adverb.
• Especially the adverb derives of course from the adjective especial, as in “an especial friend”. It is now more often just plain special in Modern English, but not always.
• Ugly comes from ug-ly, where ug comes from Old Norrs ugg(r) meaning fear or dread, and which in English survives only dialectally; ug is otherwise obsolete outside of dialect.
• Whether as adjective or adverb, early is from Old English árlíce, the positive degree of ON ǽr ‘ere’ + -líce ‘-ly’. At one point, people really did write earlily for the adverb corresponding to the adjective early, but no longer.
• Again irrespective of ad{jective,verb}, daily is from Old English dæʒlíc, a straightforward derivation of OE dæʒ with the -líc suffix. It is cognate to Old Norse dagligr.
• The adjective timely is clearly based on time, but does not occur in Old English and only rarely in Middle English. It does have an Old Norse cognate in tímaligr meaning temporal. The adverb version in Old English was tímlíce, from the OE substantive tíma time plus the ‑ly suffix. So as an adverb it was certainly around in Old English, and that may be where the adjective version comes from.

I’ll get back to your original question RSN*, but first let’s look at both forms of the suffix.

_{Where RNS of course means “real soon now”. It does not mean “*really soon now”}.

The OED on ‑ly¹

Here is a small excerpt from the OED for the first ‑ly suffix:

The original Teut. adjs. in -lîko- were compounds of the

sb. *lîkom appearance, form, body (see lich). Thus *mannlîko- (‘manly’) means etymologically ‘having the appearance or form of a man’; gôðolîko- (‘goodly’) ‘having a good appearance or form’, or ‘having the appearance or form of what is good’. The primitive force of the suffix may therefore be rendered by ‘having the appearance or form indicated by the first element of the word’; but while in the historical Teut. langs. it has remained capable of expressing this meaning, it has in all of them acquired a much wider application.

When appended to sbs., the most general senses of the suffix in all Teut. langs. are ‘having the qualities appropriate to’, ‘characteristic of’, ‘befitting’. In English of all periods it has been a prolific formative; the adjs. formed with it are most frequently eulogistic, as in kingly, knightly, masterly, princely, queenly, scholarly, soldierly (cf. manly, womanly with mannish, womanish); among the examples with dyslogistic sense are beastly, beggarly, cowardly, dastardly, rascally, ruffianly, scoundrelly. In OE., as in other Teut. langs., the suffix had often the sense ‘of or pertaining to’; but the adjs. have, so far as this meaning is concerned, been to a great extent superseded by synonyms of Latin or Romanic etymology. Thus manly formerly admitted of the senses now expressed by human and masculine; for one of the older senses of timely we must now say temporal. Another use of the suffix, common to English with other Teut. langs., is to form adjs. denoting periodic recurrence, as daily, hourly, monthly, nightly, weekly, yearly.

When -ly is appended to an adj., the resulting derivative adj. often connotes a quality related to or resembling that expressed by its primary; cf., e.g., OE. léof ‘dear’ with léoflic ‘lovely’ (or, as it might be rendered, ‘such as becomes dear’). The diminutive sense found in mod.G. gelblich yellowish, süsslich sweetish, though a very easy development from the original sense of the suffix, does not seem ever to have existed in English. Even in OE. -lic had app. ceased to be used in new formations from adjs.; the new adjs. f. adj. + -ly that have arisen in ME. or in mod.E. seem to be from the advs.

There is a lot more where that came from, too.

The OED on ‑ly²

For the second version, here is another brief excerpt:

The form-history of the suffix in Eng. is similar to that of -ly¹:

in ME. the OE. -líce was normally represented by -līche (southern), -līke (northern), the compar. being -lī̆ker, -luker, -loker (superl. -est).

The form -li, -ly, which was current in East Midland English in the 14th c., and became general in the 15th c., is probably due to the influence of the ON. -liga. In the strongly Scandinavianized dialect of the Ormulum (c 1200) -liʒ and -like are used indifferently, according to the requirements of the metre. Where the positive ended in -li, -ly, the comparative and superlative ended in -lier, -liest. In the 15–17th c. forms like falslyer, traitorouslyer (Malory), softlier, justlier, widelier (Long Barclay’s Argenis 1625), easilier, -est (R. Baxter Saving Faith 1658) were common, but in later use the advs. in -ly are compared with more, most, the inflexional forms being only employed in poetry or for rhetorical effect.

In OTeut. an adv. with this suffix must have implied the existence of an adj. with the suffix corresponding to -ly¹. In OE., however, there are several instances (e.g. bealdlíce boldly, swétlíce sweetly) in which an adv. in -líce has been formed directly from a simple adj. without the intervention of an adj. in -lic. In ME. the number of these direct formations was greatly increased, and when the final -e, which was the original OE. adverb-making suffix, ceased to be pronounced, it became usual to append -ly to an adj. as the regular mode of forming an adv. of manner. It was, down to the 17th c., somewhat frequently attached, with this function, even to adjs. in -ly, as earlily, godlily, kindlily, livelily, lovelily, statelily; but these formations are now generally avoided as awkward, while on the other hand it is felt to be ungraceful to use words like godly, goodly, lovely, mannerly, timely, as advs.; the difficulty is usually evaded by recourse to some periphrastic form of expression. In examples belonging to the 16th and 17th c. it is sometimes difficult to determine whether a writer intended the adv. goodly to mean ‘in a good manner’ or ‘in a goodly manner’, and there are other instances of similar ambiguity. In the words denoting periodical recurrence, as daily, hourly, the adj. and the adv. are now identical in form. A solitary example of an adv. f. sb. + -ly² with no related adj. is partly. From the early part of the 16th c. the suffix has been added to ordinal numerals to form advs. denoting serial position, as firstly, secondly, thirdly, etc. (cf. F. premièrement, etc.).

When -ly is attached to a disyllabic or polysyllabic adj. in -le, the word is contracted, as in ably, doubly, singly, simply; contractions of this kind occur already in the 14th c., but examples of the uncontracted forms (e.g. doublely) are found as late as the 17th c. Whole + -ly becomes wholly, but in all other similar instances the written e is retained before the suffix, e.g. in palely, vilely, puerilely. Adjs. ending graphically with ll lose one l before -ly, as in fully (in southern Eng. commonly pronounced with a single l, but in Scotland often with double or long l), dully /ˈdʌllɪ/, coolly /ˈkuːllɪ/. Adjs. of more than one syll. ending in y change y to i before -ly, as in merrily; in formations from monosyllabic adjs. the usage varies, e.g. dryly, drily; gayly, gaily (cf. daily, which is the only current form); slyly, slily (but always shyly); greyly, grayly has always y. Another orthographical point is the dropping of the e in the two words duly, truly. It is unusual to append -ly to an adj. in -ic; the ending of the adv. is nearly always -ically, even when the only current form of the adj. ends in -ic.

Back to the OP’s Question

When people say something like real good, they are using real as an adverb. This is permitted, especially in casual use in Australia and North America. The thing is, real as an adverb is not a general-purpose one. It only works on adjectives. The OED also notes that this is “Not common in standard use in southern England”. This may well be true; but there are many places where English is natively spoken outside of southern England.

About the adverb real, the OED says:

real

B. adv. ----

1. (Usually with adjs.) Really, genuinely. Also more loosely in later use (orig. Sc. and U.S.): Very, extremely.

In early use properly an adj. qualifying the phrase (‘good turn’, etc.) which follows, and only at a later period apprehended as an adv. qualifying the adj. (‘good’, etc.). Not common in standard use in southern England except to some extent in the orig. construction.

• 1658 Whole Duty Man xiii. §35 ― The reallest good turn that can be done from one man to another.
• 1718 J. Fox Wanderer No. 17. 116 ― An Opportunity of doing a real good Office.
• 1771 Mrs. Griffith Hist. Lady Barton II. 283 ― The burning of three real good and substantial houses in this town.
• 1827 R. H. Froude Rem. (1838) I. 448 ― Last Friday was a real fine day.
• 1885 G. Allen Babylon vi, ― It looks real nice.
• 1887 Mabel Wetheral Two N.-C. Maids xxv. 174, ― I was real put out to think how [etc.].
• 1939 War Illustr. 28 Oct. 219/1 ― If I had not been on fire I could easily have shot down two more. It was real bad luck, but my pals accounted for three besides the one I hit.
• 1943 K. Tennant Ride on Stranger viii. 77 ― He’s real clever.
• 1959 J. Ludwig in Tamarack Rev. Summer 7 ― Some day she’d get real tough with her son Sidney.
• 1968 Globe & Mail (Toronto) 17 Feb. 50/3 (Advt.), ― Austin Healey Sprite black, radio, a real nice car.
• 1968 K. Weatherly Roo Shooter 111 ― It was real heavy going, and I must have dried the flamin’ plugs and points twenty times.
• 1976 Daily Mirror 18 Mar. 24/4 ― I’m havin’ a rest-I feel real listless.

2. (with advbs.) colloq. (chiefly N. Amer. and Austral.).

• 1893 H. A. Shands Some Peculiarities of Speech in Mississippi 52 ― Real down... Used by cultivated whites to mean exceedingly or extremely. A thing that is extremely nice is said to be real down nice.
• 1924 J. C. French Writing x. 290 ― Avoid: They live good in that camp (say live well), I sure will write real soon (say surely will, really soon).
• 1933 R. L. Pooley in Amer. Speech VIII. 61/2 ― One such [grammarian], commenting on the sentence, ‘I will write real soon,’ corrects real to read really. This is utter nonsense. No one ever says I will write really soon... It simply isn’t English.
• 1942 Z. N. Hurston in A. Dundes Mother Wit (1973) 225/1 ― De man looked at me real hard for dat.
• 1947 K. Tennant Lost Haven xix. 317 ― Everyone said she was lucky... Everything fell out ‘real nice’ for her.
• 1959 Weekly Times (Melbourne) 30 Sept. (Advt.), ― How about picking up your phone and asking your B.F.E. dealer to arrange a free demonstration of a ‘35’ on your property real soon?
• 1967 G. Jackson Let. 13 July in Soledad Brother (1971) 121, ― I felt real bad about that.
• 1975 D. Lodge Changing Places ii. 57 ― You and I must have lunch together real soon.

This happens a great deal. If you look for the word real in COCA followed by an adjective, which is something that’s real easy to do, you will find that the top ten adjectives that follow real immediately are:

1.   good          1378 
2.   quick          858
3.   hard           541
4.   bad            483
5.   nice           422
6.   big            341
7.   fast           258
8.   political      253      
9.   close          240
10.  simple         222     

Other popular choices include easy and happy.

So as I said, it happens — and not just a little, either: it happens a lot. The OED describes it, then COCA gives you a feel for the common adjectives which the adverb real collocates with.

Now, this situation can be uncannily knickersnitting to certain people. The kind of people it upsets are the ones more interested in telling you what you should say then they are in listening to what you do say. Prescriptive ‘grammarians’ and hen-pecked proofreaders who’ve been given their marching orders oft will auto-correct that real good to really good, at least in formal writing. but there is a long history of real being used without an ‑ly suffix.

But it is how real people really talk, and so to the descriptivist, it merely represents an alternative way of saying the same thing.

However, it is now looked at rather poorly in some quarters, though. Indeed, its use has come to be a class marker. So do not be surprised to see it turned into really when used as an intensifier.

All these rigid “rules” about parts of speech are after-the-fact creations. There are more kinds of words than the original eight parts of speech, and intensifiers are one of them. Fast cars can go real fast, and they can go really fast, but they cannot speed very. Notice how a car that’s really speeding is different from a car this is speeding really.

Real language is much more complicated and nuanced than a third-grader’s grammar book will ever reveal. If you want a simplified version of reality, by all means, read the third-grader’s book. Just understand that it isn’t real good at telling you anything about how real people really talk. It’s all something something of an inconvenient lie, or at best, so simplified a version of reality as to no longer bear much semblance of the same.