The following is an unedited post created on our Tumblr page. You may find the original here.
Observant blogger @grapefruitcake, who runs a fantastic blog, please check it out if you haven’t, sent me a message a few days ago, where she points out some mistakes and concerns from a post I wrote (this is Lucky Star Parts 6 and 7.) So I’m sharing the message (with their permission, of course) with my replies in bold and in brackets 
Hello! I don’t know much linguistic terminology so I find your posts quite interesting. However, I think in some cases you are misinterpreting the Japanese. [Probably, I wrote this like at 11pm and I was a bit in a rush. It was a hectic day.]
In this post, Tsukasa’s first three lines all run together. [These are grapefruitcake’s translations.]
I always leave it until the end but
sometimes my stomach gets full and
I can’t eat it anymore or it gets eaten by my family.
There isn’t any implication that the family eats it because Tsukasa’s stomach is full. [So this is a pragmatics issue, i.e. how we’re going to interpret that last part. As far as the syntax of the sentence goes, yes, there isn’t anything to tell us definitively that her getting full is the reason for the family taking it. But in the context of things, her mention that it’s unfortunate that she’s getting full, and then the mention of her family taking it away, not to mention Konata’s addition that one should not keep the best part till the end, it seems like at least a permissible interpretation that B is caused by A.]
Then Konata says
You have to eat your favourite part first don’t you.
Plain negative form + と is short for ないといけない . The と isn’t quotative here. [Here we have two things, the use of と and the phrase ーないといけない. For starters, I agree with you, this is a shortening of that phrase. But as a linguist I’m going to hold that と is still a quotative particle, albeit not for the reason I’ve stated (we’ll talk about that in a little bit.) と marks not quotes, really, but IP’s. IP’s are inflectional phrases, who phrases with a governing verb phrase that’s undergone inflection. If it’s been inflected in the negative, it’s done that. いけない is itself a verb It’s not an interjection or adverb anything like that. So it’s behaving like と言う and と思う even though the phrase itself といけない doesn’t get translated as a quote or indirect statement, as do the others.]
Konata is saying that because Tsukasa leaves the strawberry until last, she sometimes misses out on eating it. Therefore it’s best to eat it first. [I agree.]
Later Tsukasa says 上手に食べないと 落っこちちゃうじゃない
These two lines also need to be interpreted as one sentence as the と is the ‘if’ meaning: If you don’t eat it carefully it goes and falls right?
[You’ll see in my post that I totally ignore that と. This と is a conditional conjunction. (This next part is not for grapefruit specifically but for our fellow language learners) In languages there are lots of words that indicate conditions. They’re not always clear in their logic. と is a very easy conditional marker in that in the construction “A と B,” it means “If you have A, you definitely have B.” Japanese has some more ways of expressing condition which are not so strong.]
Finally (sorry this is a bit long…) in 食べながらこうグイグイと The と here is not to do with separating oneself from bodily functions (where did you learn about this usage of と because I’ve never come across it). [Right, this is a big one. I can’t tell you exactly where I’ve seen this stuff, because it’s been two years and I don’t have the papers with me right now. What I do know for sure is that there are times where these odd separations happen (not necessarily with と but certainly with ね) because of how information is flowing and the implications of that. A good example of this is how expressing the state of the weather “暑いです” sounds odd and thus one might instead say “暑いですね” even though everyone knows it’s hot outside. I believe I’ve seen と similarly when an unpopular opinion is expressed and と there is just と思う truncated. But don’t quote me on that. On the other hand, I might be totally and utterly wrong.] It’s used after 副詞
I pressed send by accident 😦 [You are forgiven.] I meant to say, there are some 副詞 (adverbs) after which と is always used. I believe the onomatopoeic 副詞 always take と before a verb. [So again I’m going to state that と is indicating an IP, so と言う 、といけない、グイグイと, all have the same と. This simplifies things, and simplicity is better. So what’s going on here (to my understanding) with the onomatopoeia is that the と is what’s telling us that it’s an onomatopoeia, in the same way that in English we’d say “the cow says moo.” This does raise an issue, which is what exactly the verb is if I want to consider グイグイ an IP. My answer for now is that it’s だ and it’s being dropped in this case. This a bad answer as is (without some historical proof) but it’s better than saying that there is a special と that just exists for certain adverbs. In A Dictionary for Basic Japanese Grammar, you’ll find that the quotative and adverbial uses of と are listed together, which gives me some credence. (In my edition, there are pages 478-479)]
I talk a lot, but I’m agreeing with grapefruit cake on basically everything, if not the interpretation of the syntax. So yeah, moral of the story, don’t listen to me when I post past 10pm.
*Edited two sentences:” 暑いだ” to “暑いです” and “暑いです” to “暑いですね.” This was an oversight on my part, considering that i-adjectives don’t really feature だ (at least not visibly) as their copula. The functional copula is that い suffix.