Fill coverage gaps in chapters 1-11

Audited each chapter file against actual LLPSI Familia Romana content
using parallel reviewers (Claude general-purpose subagents, codex, gemini).
Each chapter gained missing vocabulary, grammar points, common-error
patterns, and exercise types. ~190 lines added across 11 files.

Highlights per chapter:
- c1: geography proper nouns, -us fem. exceptions, num-question answer pattern
- c2: -er paradigm contrast (puer/vir/liber), -que rewrite drill
- c3: interrog. vs. relative quem, neque rewrite
- c4: nullus/UNUS NAUTA, -ius vocative, eius/suus contrast
- c5: relative pron. (nom.), suus agreement, -ae ambiguity
- c6: passus 4th-decl preview, mille/milia, autem postpositive
- c7: cui drill, plenus + gen., quod (because/relative/interrog.) trap
- c8: hic/ille discourse force, UNUS NAUTA class, quantus/quot trap
- c9: stem recovery from gen., ipse emphasis target, sub + abl. for location
- c10: fera vs. ferus, abesse/adesse/ire infinitives, quia/quod synonymy
- c11: full posse paradigm, dat. of reference (mihi dolet), gaudere syntax

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

llpsi-c4.md

@@ -6,9 +6,13 @@ Topic argument supported (e.g. `/llpsi-c4 imperative`, `/llpsi-c4 vocative`, `/l
 
 ## Vocabulary (new in Cap. IV)
 
-**Nouns**: *sacculus -ī* m. (purse); *pecūnia -ae* f. (money); *nummus -ī* m. (coin); *mēnsa -ae* f. (table); *baculum -ī* n. (stick); *verbum -ī* n. (word, in chapter sense).
+**Nouns**: *sacculus -ī* m. (purse); *pecūnia -ae* f. (money); *nummus -ī* m. (coin); *mēnsa -ae* f. (table); *baculum -ī* n. (stick); *verbum -ī* n. (word, in chapter sense); *fūr, fūris* m. (thief — *Mēdus fūr est*); *Mēdus -ī* m. (servus); *Lēander -drī* m. (servus, *-er* drops *e*).
 
-**Adjectives**: *vacuus -a -um* (empty); *bonus -a -um* (good).
+**Adjectives**: *vacuus -a -um* (empty); *bonus -a -um* (good); *malus -a -um* (bad — contrast with *bonus*).
+
+**Interrogative adjective use of *quī, quae, quod*** ("which?") with nouns: *quī servus? quae ancilla? quod baculum?*; acc. *quem servum? quam ancillam? quod baculum?*
+
+**Postpositive particle**: *enim* ("for" — never first word in clause).
 
 **Numbers**: *quattuor (IV), quīnque (V), septem (VII), octō (VIII), novem (IX), decem (X)* — round out 1–10 from previous chapters.
 
@@ -56,6 +60,12 @@ Topic argument supported (e.g. `/llpsi-c4 imperative`, `/llpsi-c4 vocative`, `/l
 
 6. **Compound prefixes *ad-/ab-***: *adest* (is here, ad+est), *abest* (is away, ab+est), *adsunt, absunt*. Just lexical; not yet a productive rule for the student.
 
+7. ***nūllus* paradigm** — the **ŪNUS NAUTA** group (*ūnus, sōlus, tōtus, alter, ūllus, nūllus, neuter, alius*): pronominal endings in gen. sg. **-īus** and dat. sg. **-ī** for all genders. *nūllus, nūllīus, nūllī, nūllum, nūllō*. Recognition level only in c4.
+
+8. **Vocative of *-ius* names**: contracted to single **-ī**: *fīlius → fīlī!*, *Iūlius → Iūlī!*, *Cornēlius → Cornēlī!*. Plus the irregular vocative *meus → mī*: *mī fīlī!*
+
+9. ***suus* refers to the subject of its own clause** — works equally with plural subjects: *Iūlius et Aemilia servōs suōs vocant* (their own slaves, not someone else's).
+
 ## Common error patterns
 
 - **Vocative wrong**: student says *Mārcus, venī!* — should be *Mārce, venī!* (vocative).
@@ -64,6 +74,9 @@ Topic argument supported (e.g. `/llpsi-c4 imperative`, `/llpsi-c4 vocative`, `/l
 - **Pronoun *is* gender confusion**: *is* = he, *ea* = she, *id* = it. Student says *id* for "she" — wrong.
 - **Imperative form same as indicative**: in 1st/2nd conj., it's tempting to use *vocat* as a command — wrong, it's *vocā* (sg.). The indicative -t ending is third-person, not a command.
 - **3rd-conj. imperative -e looks like nothing**: *pōne!* is the right form; students often want *pōnī!* by analogy with *audī!* — flag the contrast (3rd vs. 4th).
+- ***suus* with 1st/2nd person subject**: Latin uses *meus/tuus* when subject is *ego/tū*. *Suus* is reflexive only for 3rd-person subjects.
+- **Confusing *quod* (rel. n.) with *quod* (interrog. adj. "which?")**: same form; disambiguate by clause shape (relative attaches to antecedent; interrog. heads a question with a noun).
+- **Imperative macron**: long *-ā* in *vocā́* distinguishes 1st conj. imperative from a hypothetical short form. Macrons matter for class identification.
 
 ## Exercise menu
 
@@ -75,6 +88,10 @@ Topic argument supported (e.g. `/llpsi-c4 imperative`, `/llpsi-c4 vocative`, `/l
 6. **Conjugation pattern**: "Give the imperative sg. and 3rd-sg. indicative of: *pōnere*." → *pōne, pōnit.*
 7. **Spot the error**: "Mārcus, vidēt baculum." → vocative wrong (should be *Mārce*); also *vidēt* has a stray macron — should be *videt*.
 8. **Number drill**: "Count from 1 to 10." → *ūnus, duo, trēs, quattuor, quīnque, sex, septem, octō, novem, decem.*
+9. **Interrogative adjective drill**: "Quī servus pecūniam habet?" → *Mēdus*; "Quod baculum sūmit Iūlius?" → *baculum quod in mēnsā est* (or similar).
+10. ***eius* vs. *suus* contrast set**: 5–6 minimal-pair sentences — student picks. "Iūlius vocat servum ___ (Iūlius's own)" → *suum*; "Iūlius vocat servum ___ (Cornēlius's)" → *eius*.
+11. **Imperative → indicative transformation**: given *vocā!*, produce *vocat*; given *audī!*, produce *audit*; given *pōne!*, produce *pōnit* — reveals conjugation class.
+12. ***nūllus* drill**: "Iūlius habet decem nummōs; Mēdus habet ___ nummum." → *nūllum.*
 
 ## Session start