P11 · The Yesterday Machine

"gacchati means 'he goes.' What about 'he went yesterday'? Three steps:
① Prepend a- (the past switch) ② Replace -ti with -t ③ Everything else stays: agacchat."
"Try with your own verbs: paṭhati → 'he read yesterday'?" (student: apaṭhat) "vadati → ?" (avadat)
"'I read yesterday' — the past ending for 'I' is -am: apaṭham."
"pūjayati → 'he worshipped yesterday'?" (apūjayat) "icchati is a little odd: a and i merge to ai — aicchat. Just get used to the sound first."

▸ The biggest payoff day for Mechanism 5: one prefix + one small set of endings, the student's entire verb inventory doubles instantly (present + past). Zero new roots. Ruppel calls a- the "marker of pastness" — in class we simply say past switch.

"Prefixed verbs (add-on parts from P09) note: the switch goes inside the add-on part, next to the root —
upaviśati (he sits down) → upāviśat (add-on upa + switch a fuse to upā). One listen is enough; full paradigm table in Crystallization Lesson."

ī-family feminines taking their case markers (low-friction track):

"The subject marker of devī is just devī itself (as easy as the kanyā family in P09), direction marker adds -m: devīm.
nadī is the same: nadī / nadīm. 'The queen went to the river yesterday' — hyaḥ devī nadīm agacchat. All three pieces are already yours."

Building blocks (use-first, analyze-later — this lesson set): adya (today) / hyaḥ (yesterday) / śvaḥ (tomorrow) — the time trio.

adya kumāraḥ paṭhati. hyaḥ kumāraḥ apaṭhat. (reads today; read yesterday — time word + tense corroborate each other.)

(RSS L6 model sentence "adya … vāsaraḥ" with native-speaker audio; hyaḥ at sentence end / before voiceless consonant stays unchanged, before voiced consonant sounds like hyo — listen only. Vocabulary self-decoding: the traditional name of this tense อนทุยตนีภูต (Thai: "past that is not of today") = an-adya-tana-bhūta 'not-today's past' — the building block adya you just received is hidden inside it. No Thai reflex, so no cognate hook is created. See 積木層研究-高頻即用塊.)

TPRS wrap-up: "Where did the queen go yesterday? What did she see? What did the boy ask?" — students assemble the story in past tense, choral recitation.