I think it's about time that people realize that learning grammar early is very detrimental in language learning process. As mentioned in the article "Nevertheless, Hamilton did not oppose the study of grammar, only its timing. “The theory of grammar should be taught only when the pupil can read the language, and understand at least an easy book in it”."
As an example in most of the Muslim majority countries, Arabic is thought as a second or third language. Apparently Arabic grammar is probably one of the hardest to learn and ironically the modern Arabic grammar was actually developed by Iranian scholars not native Arabic scholars. This makes many of the students cannot read and understand Arabic book (e.g. Quran) even after several years of studying.
The golden standards for Arabic language is the Quran. Even as the Quran has huge amount of words (~ 77,000 total words and ~ 15,000 unique words) because of its Semitic origin it only has root words of ~ 2,000 words [1].
To provide a better comparison perspective, English has ~ 10,000 five letter words and the popular word game Wordle only uses about ~ 2000 words. The entire Quran has much less vocabulary to be memorized even compared to the five letter words in English language excluding the other non five letter words that you need to memorize that is probably more than 100,000 words.
Knowing fundamentals of the grammar early helps immensely. Not learning them fully, but at least being aware of them.
E.g. the fact that there are 4 verbs moods in French - indicatif, subjonctif, conditionel and imperatif - is usually explained few weeks, if not months, into learning the language. Having been through this, I would've much prefered this to be mentioned right away, because it greatly helps with making sense out of written text. I am a computer programmer however, so it might not apply to everyone.
Ditto goes for verb conjugation comprising two distinct classes - regular and compound. Trivial to explain, yet it's inevitably smeared across several weeks, confusing the heckout of the otherwise trivial subject.
Another e.g., also from French, its alien-structured use of pronoms. This too IMO needs to be explained in first few days into the language. Yes, you can go by example here, but a single hour of explaining this will greatly simplify groking of all the examples that will follow.
As an example in most of the Muslim majority countries, Arabic is thought as a second or third language. Apparently Arabic grammar is probably one of the hardest to learn and ironically the modern Arabic grammar was actually developed by Iranian scholars not native Arabic scholars. This makes many of the students cannot read and understand Arabic book (e.g. Quran) even after several years of studying.
The golden standards for Arabic language is the Quran. Even as the Quran has huge amount of words (~ 77,000 total words and ~ 15,000 unique words) because of its Semitic origin it only has root words of ~ 2,000 words [1].
To provide a better comparison perspective, English has ~ 10,000 five letter words and the popular word game Wordle only uses about ~ 2000 words. The entire Quran has much less vocabulary to be memorized even compared to the five letter words in English language excluding the other non five letter words that you need to memorize that is probably more than 100,000 words.
[1] The Clear Quran Series Dictionary:
https://theclearquran.org/dictionary/