---

All answers having "Jargon" as clue:

3 Character Answers:

---

LEE



4 Character Answers:

---

CANT



5 Character Answers:

---

ARGOT

ESSEX

IDIOM

LINGO

SLANG

TABOO



6 Character Answers:

---

PATOIS

PATTER

SKIVVY



7 Character Answers:

---

DIALECT



8 Character Answers:

---

DOGLATIN

LEGALESE

PIGLATIN



9 Character Answers:

---

RIGMAROLE



11 Character Answers:

---

DOUBLEDUTCH



12 Character Answers:

---

GOBBLEDEGOOK

GOBBLEDYGOOK