the most important concept of the entire book, is that each spouse is supposed to learn the other person's "Love language", and speak it to them.(ie: find out how they like it, and then give it to them how they like it) It is most definately not, "each spouse is supposed to learn how to interpret the other person's 'language', and learn to like it the way they say it".
I don't recall Lil expressing what the most important concept of the entire book was, nor did she assert that you were supposed to learn how to interpret... You seem to be arguing against points she never made.
Her experience with her BF has revealed that he expresses his love/affection via acts of service. Chapman wrote: "We tend to speak our primary love language, and we become confused when our spouse doesn't understand what we are communicating." So, while the expression and the desired LL may not be identical 100% of the time, it appears that the originator of the concept points out the tendency for the them to be the same a high percentage of the time.
Lil has the maturity to recognize, accept and give credit for her BF's acts of service even if they aren't her primary preference. Doesn't mean that she wouldn't prefer to receive personal, well-thought out gifts from him. But, there's nothing wrong with choosing not to spit on or discount what he does offer, nor is it an indication that she doesn't get the concept.
