P04 · Week 4 · Lesson

P04 · i-Stem

Same Hat Set, Different Stem

Draft · in review

Teacher notes / sources (students may skip)

Corresponds to: SKT บทที่ 4 ＝ Perry i-stem unit (§113 agni table, §114–115 vāri etc.; the original book has a lesson boundary crossing III/IV with some OCR duplication — follow § numbers). This lesson is the first transfer test of the noun system: the hats (-ḥ/-m) stay the same; the stem shifts from -a to -i — rāmaḥ:rāmam :: agniḥ:agnim. Sandhi batch two: -iḥ before voiced consonants → -ir. Full table (agni eight cases, vāri neuter) → Crystallization Lesson W5 second. Prerequisite: the agni-table crit fix in SKT volumes 1–5 must be complete (check P1 item; advance-verify against the W5 deadline in the course calendar).

① AnchorA cognate hiding in Thai — recognise it first, then learn its form0. Anchor (5 minutes)

"Three new friends, all from families you have already claimed: อัคนิ (Thai: "fire god, agni"; also written อัคนี) ← agni (fire); ฤๅษี (Thai: "hermit, sage") ← ṛṣi (sage — ★the standard demonstration word for rule B1 and ฤ); ทุกข์ (Thai: "suffering, dukkha") ← duḥkha (suffering — see the killer mark on ข์? It hides the ḥ that sits in the middle of the Sanskrit word). And one beautiful one: วาริ (Thai: "water, poetic register"; also common as วารี, RID standard form is วาริ) ← vāri (water)."

② StoryA micro-story you can follow, with only one new form1. Story (CI micro-narrative)

๑

ऋषिः नगरम् गच्छति।

ṛṣiḥ nagaram gacchati.

The sage goes to the village.

๒

किम् ऋषिः वदति।

kim ṛṣiḥ vadati?

Does the sage speak?

๓

न वदति। अग्निम् इच्छति।

na vadati. agnim icchati.

He does not speak. He wants fire.

๔

कुमारः वारि इच्छति।

kumāraḥ vāri icchati.

The boy wants water.

(In connected reading of sentence ๔, vāri + icchati fuses into vārīcchati — two i's meeting merge into long ī. Vowel sandhi will be covered in the W5 Crystallization Lesson; for now, just listen, don't write.)

③ Sentence-buildingBuild it sentence by sentence from words you already have2. Sentence-Building (MT track)

"New word: agni (fire). Its stem ends not in a, but in i — but the hats are the same set:
subject hat agniḥ, direction hat agnim. 'The sage wants fire'?"
(Student constructs: ṛṣiḥ agnim icchati — teacher confirms, then demonstrates connected reading ṛṣir agnim icchati)

▸ Transfer test (mechanism 5 on the noun side): rāmaḥ:rāmam :: agniḥ:agnim :: ṛṣiḥ:ṛṣim — "Change the stem at will; the hat logic does not change. This is where Sanskrit nouns make sense."

"Listen to the connected reading again: ṛṣiḥ nagaram → ṛṣir nagaraṃ. That breathy sound becomes r before a voiced consonant.
Last week -aḥ became o; this week -iḥ becomes ir — the same family of rules. Let your ear remember first."
"Freebie: vāri (water) is neuter — subject hat ＝ object hat ＝ vāri as is; you don't even need -m."

Building blocks (use-first, analyze-later — this lesson group): api (also) ＋ eva (precisely, just)

ṛṣiḥ api agnim icchati (the sage also wants fire); kumāraḥ eva vāri icchati (it is specifically the boy who wants water)

(Both are pure invariable particles — no Thai cognate reflex; use directly as building blocks, no inflection; formal home is the invariable layer; RSS frequency: eva 3.9%, api 3.6%. Details in 積木層研究-高頻即用塊.)

④ DripGrammar one line at a time; the full table comes at the crystallization lesson3. In-Line Drip (four lines)

Listen4. Listening (audio list)

▶ audioAudio checklist for this lesson — placeholders in the preview; the live version uses pre-baked Matcha audio + real recordings (played when logged in, not hot-linked).

All four story sentences in both versions; comparison clips: ṛṣiḥ (sentence-final) vs ṛṣir nagaraṃ (before voiced) vs ṛṣiḥ paṭhati (before p); vāri icchati ↔ vārīcchati pair (listen only); single words agniḥ/agnim/vāri.

Use5. Use (Exercises)

Hat + stem swap matrix drill: rāma/kumāra/agni/ṛṣi × subject hat/object hat (oral, recast).

Sandhi listening discrimination: -iḥ or -ir? (five examples, follow up by asking whether the next consonant is voiced or not)

padapāṭha reconstruction: hear ṛṣir nagaraṃ gacchati, write ṛṣiḥ nagaram gacchati.

Decode reclaim: คีรี (Thai: "mountain, peak; as in place name เขาคีรี") ← giri (mountain), ชน (Thai: "people, folk; as in ชนบท") ← jana (person), ทุกข์ (Thai: "suffering, dukkha") ← duḥkha — all three are in the Perry vocabulary list for this lesson.

kośa intakeThis lesson's words enter your personal word-store6. kośa (personal word-store, this lesson)

Vocabulary cards: agni अग्नि (fire; อัคนิ/อัคนี), ṛṣi ऋषि (sage; ฤๅษี ★B1), vāri वारि (water; วาริ), duḥkha दुःख (suffering; ทุกข์, Decoder Card D2 example). Sandhi card: -iḥ + voiced consonant → -ir (with audio). Operation card upgrade: -ḥ/-m hat card — add note "applies to all stem types." Building-block cards: api (also), eva (precisely) — pure invariable particles, no inflection.

Crystallization linkCrystallization Bridge

→ Crystallization Lesson W5 second: comparative table of a/i/u stems (deva/agni/guru side by side) + vāri neuter table + verb class 1/4/6/10 comparative table. By then students will have used -ḥ/-m for all three stem types in actual sentences.