26362 Though I speak with the tongues of men and of angels….

A tough one, this, which took me past the 30 minute mark by 2.22, but hey, at least I was error free. At the time of writing, everyone else on a small sample has a single error, and I’ve already wasted some time trying to figure what this might be. For me, the main retardant factor was/were the many well-disguised definitions, leaving very little chance of bunging in from definitions. Just to throw you off the scent, there’s the odd barely cryptic clue which might well leave you floundering looking for something more complex.
It might help you to solve this thing if you are a charismatic Christian with a penchant for Yiddish, French and cricket, though I expect that narrows the field rather. Here’s how I extracted the wheat from the chaff.

Across

1 PICOT Decorative loop
At a stretch, you could make this apply to François-Édouard Picot, purveyor of tasteful pre-photographic pornography to French salons, but it’s really just a loop of some kind in fabric. Easy wordplay, thank goodness: CO, the conventional crossword firm, held by PIT, that sort of mine.
4 FORESIGHT Vision
As in seeing something before it happens. ORES are minerals, FIGHT is box. Insert part a into part b.
9 SQUARE LEG position in field
Easy if you’re into cricket, just giving you just, SQUARE, left L, and say EG. Roughly where the umpire stands when he’s not behind the stumps.
10 LIFERperson given sizeable bird
Bird is one of those many euphemisms for a prison sentence, here derived form CRS bird lime/time. Hidden and reversed in featuRE FILm
11 COZENS Tricks
I thought the wordplay was in the blink-and-you-miss-it category. You get the COS from “for informally”, deriving from “because”. ZEN is a branch of Buddhism (and a useful word in Scrabble).
12 EMENDATE Fix
Appointment provides you with the DATE to tack onto the back of E(nergy) MEN (people)
14 DRAG ONES FEETKind of &lit
If you want to go fast, you would have to take a revisionist attitude to dragging your feet. The revision of GO FAST? ER, NEED gives you the not-fast practice.
17 ALADDINS CAVE place of treasure
A boy’s gives A LADS. Watch is CAVE, public school slang for look out or beware, which you would know if you paid attention in Latin classes. The Romans used to warn people of the family dog with a mosaic including the words cave canem, this onefrom Pompeii. Tricky if the dog died: you’d have to rearrange al those little bits of stone, and cave gerbillinam probably doesn’t suggest the same threat level. Keep cave, by extension, means to keep a lookout.
When you’ve worked that out, set ALAD’S and CAVE around D(aughter) IN. Open sesame.
20 PINT-SIZE pocket
As in pocket battleship, a smaller version of the real thing such as the Graf Spee. “Unusual” telegraphs an anagram, count through the letters until you get to 8 and you’ll have ZIP SET IN.
21 BOWYER one provided for the Archers
The grammar works thus: one (of this profession) provided (material, sc bows) for the Archers. In the wordplay, the country cottage turns out to be a BOWER (especially if you’re being poetical) and Yen provides the Y, or I suppose strictly the ¥, to be inserted
23 CARPI Bones
Specifically of the wrist. You have three words all translating to CARP, two verbs and a noun. Add “one”.
24 OVERDRAFT a figure in red
Comprised of completed = OVER and sketch = DRAFT,a and not variations on DRAWN.
25 DIRIGISME state control
Desperate = DIRE, one is i (and all alone?) and device is GISMO, which for our purpose has to be cut short.
26 NASTY rank
Line is DYNASTY, from which you remove the leading couple of letters

Down

1 POSTCODE conclusion to address?
Not if you’re a kid and adding England, UK, Europe, the Earth, Solar sytem, Outer spiral arm, the Galaxy, the Universe to your address to make it really complete. Following POST, joke COD, ultimately lame E.Took ages to spot that definition and that LUD is not a word meaning joke.
2 CHUTZPAH Audacity
Means dam’ cheek in Yiddish. A boy kills both his parents and pleads for mercy because he’s an orphan. CHurch, state is UTAH, unknown Z and Power for the P. Assemble. Nice to have a whole state and not just its abbreviation.
3 TORONTO BLESSING Varied reactions of worshippers.
Some of us were rather hoping the rest of the world had forgotten this, and it’s quite a surprise to find it both in a crossword and the dictionaries. The Toronto blessing has a specific start date and place, January 1994 at Toronto Airport Vineyard Church, and was a form of Christian revivalism characterised by wild and unpredictable behaviour. According to taste, it was either a wonderful outpouring of the Holy Spirit which we just have to import into our Church, or an outbreak of hysterical behaviour which we certainly wouldn’t want to see at Evensong, thank you very much. Derive it (if you can) from TO RON (boy) + TO (again) B(ritish) LESSING (novelist, Doris I think).
4 FOLD Triple definition
Perhaps deliberately in close proximity to the previous clue. Fold can mean gather, as in pleat, Church, as in “other sheep I have which are not of this fold”, and close as in what a company will do when bankrupt.
5 RAGAMUFFIN little scruff
As in street urchin. Paper is RAG (especially if our dear sister paper, the Sun) MUFFIN is, in some confectioners universe, a roll*. You need to tear a space for the innocent little A.
* for the benefit of our Stateside friends, a muffin is not an oversized, over sweetened cake with blueberries in it, but a bready thing you get your fag** to toast over an open fire, and you then consume it with butter. I believe you call them English muffins. In the current UK, sadly, it’s more likely to be an oversized….
** oh, dear, I can see this getting awkward.
6 SILENCE IS GOLDEN Peace
…is the only definition I can conjure out of the clue. Or in the worplay is GOLD(EN) which in the proverbial sense is the equivalent to SILENCE. This might be a sort of strained &lit, or perhaps wordplay without definition. Not my candidate for clue of the day: needs more work, I think, though I’m open to enlightenment.
7 GUFFAW a loud laugh
Codswallop is, in one of its senses, nonsense, here represented by GUFF. Add A(nswer) and W(ith).
8 TURKEYFaiure
An old jailer is a TURNKEY. Remove his N(ame)
13 RENDEZVOUS Meeting
Chaotic signals a rather unlikely looking anagram. Use DOZENS RUE V(ery)
15 MAN YEARS such a lot of work
Split the answer 4,4 and you have MANY EARS, bags/lots of corn
16 SECRETLY in disguise
Flash provides the SEC(ond), count (more usually with on) gives RELY. Bottom of street in a down clue gives T. Assemble
18 SPICED with mace
The question mark shows we have an example of spice. An agent “tailed” (as in topped and tailed) gives SP(y). ICED for finished off turns up again
19 SNORER One sleeping soundly
Ie with a lot of noise. Almost a cryptic clue!
22 PEKE dog
Sounds like peak, top.