The Spanish for “chest”, pecho, sounds completely different than the English chest.
The relationship is the Latin -ct- words transforming into -ch- as Latin turned into Spanish. Thus, the pect- maps to pech- exactly. The English word, on the other hand, is taken – unchanged – directly from the Latin.
Also from the same root, in Spanish, es pechuga — the common word for the common food, “chicken breast”!
The law and the good, in European languages, are associated with straight lines; the bad with the crooked. Think about the word crooked itself, literally! Or about right/rectangle, or the Greek ortho– for straight, hence, orthodox as well as orthodontics.
The “ct” in the original direct turned into a “ch” in Spanish, in the usual pattern of “ct” turning into “ch” as Latin grew into Spanish.
The Spanish for “night”, noche, is related (via the common Latin ancestor) nocturnal.
Here’s the interesting part: the Latin sound “ct” consistently changed to the “ch” sound in Spanish. Think “lactose” and “leche”, or “octagon” and “ocho”. And this is another example of that pattern: the “ct” in “nocturnal” is the same as the “ch” in “noche”!
Leche is a first cousin of the English lactose via a very interesting pattern: the -ct- to -ch- pattern.
Both come from the same Latin root, lactatio (literally, “suckling.”) The -ct- in that root remained unchanged as it entered English (because it entered via the sophisticated French) but that sound almost always turned into a -ch- sound as Latin evolved into Spanish. Thus the l-ct maps to the l-ch almost exactly.
Thus decir is another example of the “ct” sound in Latin turning into the “ch” sound in Spanish — and is also related to the English word… dictionary.