Parashas Eikev · Passuk 11:19
and teach them to your children—reciting them when you stay at home and when you are away, when you lie down and when you get up;
Torah Temimah points to Berakhot 15b.
TT lemma: ולמדתם מהו ולמדתם – שתהא למודך תם, שיתן ריוח בין הדבקים, כגון בכל לבבך (unit 1 of 10).
English: What is “you shall teach them”? That your learning be complete (tam) — that one leave a space between letters that could stick together, for example in “bechol levavcha,” “al levavecha,” “bechol levavchem,” and similar phrases, so that one does not swallow a letter and blur the reading.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13
The Gemara uses this passuk in a sugya (proof, illustration, or dispute). Named as one of R' Yishmael’s 13 or R' Eliezer’s 32 only when that move is explicit.
Teaching includes clear articulation: the learner must separate the joined letters so the words of Shema stay distinct.