It depends on who's saying it, and what idiolect they're speaking. Some people sometimes put an epenthetic shwa between /k/ and /r/ in /krai/ to break up the cluster, and/or make the /r/ syllabic, and/or split the diphthong /ai/ into two pieces. And other times, they don't. It's not standard, sorry. It can vary from one to (in extreme cases, like the Johnnie Ray song) four or more.
Don't start with English writing, or you'll never get anywhere. Syllables are units of aural perception, not of writing; if you're still thinking of cry as containing a "Y", I'm afraid you're gonna hafta learn a whole lotta phonetics.
Start, if you must, with standard phonemic representations like the ones in Kenyon and Knott.
If you use the real OED, you will find all these with no trouble:
burlily, chillily, cleanlily, comelily, deadlily, friendlily, ghastlily,
ghostlily, godlily, holily, homelily, jellily, jollily, kindlily, livelily,
lonelily, lordlily, lovelily, lowlily, manlily, melancholily, oilily,
portlily, sicklily, sillily, sprightlily, statelily, surlily, uglily,
unfriendlily, ungodlily, unholily, unmanlily, wilily, woollily, worldlily.
So there is clearly ample evidence that this sort of thing exists.
Here in more detail is the OED entry for sillily:
sillily [ˈsɪlɪlɪ], adv.
Etymology: f. silly a. + -ly 2.
Poorly, badly. Obs. rare.
- 1581 Mulcaster Positions xxxv. (1887) 126 — The soule it selfe is but sillyly looked to, while the bodie is in price.
- 1611 Cotgr., s.v. Manger, — He that makes himselfe simple shall be sillily vsed.
In a foolish, absurd, or senseless manner.
- 1627 W. Sclater Exp. 2 Thess. (1629) 256 — How doe wee sillily call all Idolatrous, that is in vse amongst Idolaters?
- 1658 A. Fox Würtz’ Surg. iii. xi. 248 — Such Wounds which were very deep, and were silily and ignorantly stitched.
- 1712 Steele Spect. No. 466 P6 — [She] affects to please so sillily, that..you see the Simpleton from Head to Foot.
- 1740–1 Richardson Pamela I. xxiv. 67 — He sat down, and look’d at me, and..as sillily as such a poor Girl as I.
- 1805 Spirit Publ. Jrnls. IX. 4 — They sillily interested themselves in the event of a new experiment.
- 1843 Mrs. Carlyle Lett. I. 254 — Neither have I sillily paid four or five pounds away for it.
- 1864 Browning Dram. Pers. Wks. 1896 I. 573/2, — I took your arm And sillily smiled.
So it has clearly been around for a long time.
That should answer your question about whether sillily is “valid English”. Sure, you may not care for it, but it is unquestionably an English word of long-standing use.
Best Answer
The Phonetic Word Search website returns nearly 12,000 one-syllable words — input !* @ !* to the search function.
Some of these words have two pronunciations. For example, the database has both a one-syllable pronunciation and a two-syllable pronunciation of fire. So you should think of this as the number of words that can be pronounced with one syllable.
Further, many of these words are extremely rare, so you should probably view this as an upper bound.