Praise be to Allāh, the Lord of the Worlds;
No scholar has questioned the general obligation of learning Arabic language, and there is a unanimous consensus between them on the general obligation of learning and teaching Arabic. But the scholars have ruled that this obligation is a [general] duty incumbent on the community and not on each individual. As Ibn Taymiyyah said in "Mağmū‘ al-Fatāwā" (32/252), "It is well known that learning Arabic and teaching it is a collective obligation (i.e. if some people fulfil it the rest are relieved of the obligation)." And he said also, "Moreover, the Arabic language itself is part of Islām, and knowing Arabic is an obligatory duty. If it is a duty to understand the Qur‘ān and Sunnah, and they cannot be understood without knowing Arabic, then the means that is needed to fulfil the duty is also obligatory." However, "There are things which are obligatory on all individuals, and others which are obligatory on the community (i.e. if some people fulfill them the rest are relieved of the obligation)." (Ibid. 1/469) Indeed, as I said, whatever it takes to fulfill an obligation is also considered as an obligation based on the fundamentals of jurisprudence ruling, “Whatever is required to fulfill an obligation is itself an obligation” (mā lā yatimmu al-wāğibu illā bihi fa-huwa wājibun). [Cfr. "al-Baḥr al-muḥīṭ fī uṣūl al-fiqh" by Imām al- Zarkashī] This is a general rule, it applies to everything that is obligatory in religion. And as I mentioned, "Obligatory is what one is rewarded for doing and punished for omitting." (fa-l-wāğibu mā yuthābu ‘alá fi‘lihi wa yu‘āqabu ‘alá tarkihi) [Cfr. "al-Waraqāt fī uṣūl al-fiqh" by Imām al-Ḥaramayn al-Juwaynī] So it is an individual obligation incumbent upon every adult and sane man to learn that part of Arabic language which is absolutely indispensable to perform the [obligatory] prayers and the other [obligatory] rituals of worship, and whoever does not strive to fulfill this duty, even though he was able to fulfill it, then has committed a sin of negligence, except in the case in which he has recently entered Islām and did not know about a particular duty as the duty of the five daily prayers.
And Allāh knows best.