1: διδαχή
(Strong's #1322 — Noun Feminine — didache — did-akh-ay' )

akin to No. 1, under DOCTOR, denotes "teaching," either (a) that which is taught, e.g., Matthew 7:28 , AV, "doctrine," RV, "teaching;" Titus 1:9 , RV; Revelation 2:14,15,24 , or (b) the act of teaching, instruction, e.g., Mark 4:2 , AV, "doctrine," RV, "teaching;" the RV has "the doctrine" in Romans 16:17 . See NOTE (1) below.

2: διδασκαλία
(Strong's #1319 — Noun Feminine — didaskalia — did-as-kal-ee'-ah )

denotes, as No. 1 (from which, however, it is to be distinguished), (a) "that which is taught, doctrine," Matthew 15:9; Mark 7:7; Ephesians 4:14; Colossians 2:22; 1—Timothy 1:10; 4:1,6; 6:1,3; 2—Timothy 4:3; Titus 1:9 ("doctrine," in last part of verse: see also No. 1); Titus 2:1,10; (b) "teaching, instruction," Romans 12:7 , "teaching;" Romans 15:4 , "learning;" 1—Timothy 4:13 , AV, "doctrine," RV, "teaching;" ver. 16, AV, "the doctrine," RV, (correctly) "thy teaching; 1—Timothy 5:17 , AV, "doctrine," RV "teaching;" 2—Timothy 3:10,16 (ditto); Titus 2:7 , "thy doctrine." Cp. No. 1, under DOCTOR. See LEARNING.

2—Timothy 4:2Titus 1:9Matthew 15:9Mark 7:7Hebrews 6:1