Direct Python Instruction from Lower Primary: A Reading-Fluency-Anchored Feasibility Analysis

Vietnamese gifted-track informatics teachers periodically ask whether Python can be the entry programming language at lower primary — Vietnamese grades 3–4, learner age 8–10 — without a Scratch, ScratchJr, or Hedy precursor. The sibling node A2.5 has established that direct Python at grades 5–7 is feasible for the gifted cohort under three measurable entry criteria; pushing entry two grades earlier raises a sharper question because lower-primary learners sit at the orthographic-fluency transition that Chall calls stage 2 (confirmation and fluency, ages 7–8) into stage 3 (reading for learning, ages 9–13) and that Adams describes as the period in which alphabetic-orthographic mapping must become near-automatic before extended decoding tasks are sustainable. This paper conducts a literature-substrate feasibility analysis indexed to reading fluency. We adopt four operational feasibility criteria — reading fluency (sustained decoding of mixed Vietnamese-English orthographic content), error-density tolerance (rate of syntax and runtime errors per minute under self-paced editing), type-error tolerance (capacity to interpret a Python TypeError or NameError as informative), and syntax-grain compatibility (whitespace-assyntax, single-character operator precedence). Applied against the reading-development literature (Chall, Adams, Ehri), the cognitive-load literature (Sweller; Sweller-Ayres-Kalyuga 2019), the novice-difficulty literature (du Boulay; Sorva notional machines; Sajaniemi roles-of-variables), and the very-early CS pedagogy literature (Bers ScratchJr; Hermans Hedy; Bau Pencil Code; Kalas primary-school programming; Carlisle and Powers on flowchart and Alice CS0), the analysis concludes that direct Python from grade 3 is not feasible under the no-cohort scope without a reading-fluency-conditional gating: feasible from grade 4 exit (post-Chall stage 2) under three of four criteria, marginal under syntax-grain. A worked 8-week grade-3 module specification is provided as the limit case. The paper triangulates against A2.5 grade-5-7 results and feeds the Python Pathway Vol 0 design.