Torah Im Derech Eretz from Rabbi Joseph Soloveitchik

"There are religiously committed Jews who are indifferent to
the concerns of the larger non-Jewish society. They are content
to reside in isolated communities with unconcern, if not actual
disdain, for the Gentile world and for the problems which afflict
humanity. This introversion can be explained as a reaction to
the centuries-old derision and persecution which have been the
Jewish historical experience and to which they were subjected
with particular ferocity in modern times. Nowadays, there are
particular aspects of moral perversion afflicting the general
society which are repellant to Jewish sensibilities. Nevertheless,
this insularity cannot be vindicated as authentic Judaism even if
it can be understood and justified in particular historical periods
and situations. "

Rabbi Joseph Soloveitchik, Man of Faith in the Modern World, p. 73.

More on The Importance on Fluency in Hebrew

“In Israel, the language of the Siddur, the language of the Chumash, the language of the Tanach is the lingua franca and the most secular Israeli can read Chumash with a little bit of work better than a kid who has gone to day school here [in Canada] for whatever years. A little bit of work just to get the syntax, etc. But Hebrew is – I believe this strongly –  Hebrew is the key to almost everything in Judaism from a skill set perspective. If you have Hebrew – many of us grew up in an Ivrit b'Ivrit generation and that is not the case now, there's a sense of oh if I teach in Hebrew I won't be able to teach as much Gemara, I won't be able to taech the Ramban and the Rashi the same way. To me it seems like once a person has the real skills in Hebrew they'll get the other thing. It was a wrong educational turn [moving away from instruction in Hebrew], but there are reasons for that.”

Professor Adam Ferziger, “Between East and West Israeli Religious Zionism and American Modern Orthodoxy,” 9:06, Audio lecture at Torah In Motion.

The Torah Im Derech Eretz of Rabbi Soloveitchik - An Example

"The aftermath of Israel's invasion of Lebanon in 1982, and the attack on the Palestinian refugee camps by Lebanese Christians, left a moral stain on Israel. In the Knesset there was a demand for a thorough inquiry into the massacres and a clarification if Israel was in any way responsible. The left wing political parties were in favor of the inquiry. The right wing parties were opposed to it. Mizrachi joined them in opposing any inquiry. Rav Soloveitchik was informed of the position taken by Mizrachi. A vote was scheduled for a Sunday. The Rav called Rabbi Friedman at the Jewish Agency and instructed him to call Israel in his name and to demand that Mizrachi vote for the resolution. The Rav said that it is not a political issue but a moral one and Mizrachi had to act morally. So insistent was the Rav that he told Rabbi Friedman to call Israel on Shabbat to convey his message! The call was an halachic order by the Rav to Rabbi Friedman. The call was made on Shabbat. Mizrachi voted for the inquiry."

Orthodoxy Awakens, The Belkin Era and Yeshiva University, Victor Geller, p. 258

Tefillin on Chol Hamoed by Daniel Adler

Tefillin on Chol Hamoed

Yeshivos Must Teach Hebrew Language

"The indispensable basis of all is knowledge of the language, the mother tongue and the tongue of the Torah. From an early age every child in Israel should become familiar concurrently with the language of his country and with that of the writings which are to guide his life, -namely, Hebrew. In and from these writings he should derive his understanding of things and their relations, from them his ideas should be illustrated and clarified, from an early age his spiritual life should be developed by them. Anyone who realizes how a man's whole way of thinking takes its stamp and colouring from the language in which he speaks and thinks will agree with our Sages in regarding it as a matter of some consequence that the child should learn the holy language of the Scripture at an early age.' With it you place in his hands the key to realizing that the Scriptures ought to be the basis and source of his life, and also to making them actually his constant companions in life. Begin, therefore, with the language, and let him first read the Torah more with a view to enriching his knowledge of the language." 

Rabbi Samson Raphael Hirsch, Horeb 551 

Does this necessarily mean grammar and conversation? I know numerous American yeshiva bochurim who are not comfortable with Hebrew. They can manage some of the Rambam, which is easier Hebrew, and some Gemara Rashi, but there are all kinds of books that they cannot read. This after twenty years in school! A neighbor of mine tested some boys in a local mesivta in America and found that they could not read simple Hebrew text. And by read I mean understand, translate. The Orthodox Jewish world is the only society I know of that defines reading as saying words without understanding them. Anywhere else that is called illiteracy.

We are a people that describes itself as being built around scholarship. One day a week we don't allow children to play with balls because we want them to study instead - all day. We don't build ball fields in Charedi neighborhoods because we want the children to study. We pray two hours a day in Hebrew. How many Jews can read that Hebrew? I know numerous cheder children that pray without understanding a word! What is prayer if you don't understand the words? We must teach grammar. I go to shiur after shiur that consists of the maggid shiur racing through a sentence of Hebrew and translating. One does not learn Hebrew that way. The brain turns on for the English, shuts off for the Hebrew, probably not grasping much in either tongue. It's like listening to a message coming through a bad short wave radio connection. I heard an interview with a graduate of the Realschule in Frankfurt where he talked about how the children there studied grammar. And here in Horeb, Rav Hirsch clearly calls for formal language instruction as the first of seven categories of a plan for education:

We may therefore tabulate the general subjects of instruction for Jewish youth as follows:

(I) Hebrew language.
(2)Vernacular.
Concurrently and as living languages at an early age along with general knowledge and development of the mind.

(3) Torah, Nevi'im and Kethuvim.....

Rabbi Samson Raphael Hirsch, Horeb 552 

He doesn't say to study Chumash with a translation. He says to study Hebrew language. It comes before Tanach! Why? Because you can't read a Hebrew text without knowing Hebrew well. And to know it well you must study it as a language, by itself so that it becomes a living language, which means a language one can speak. And as we know Rav Hirsch was not a Zionist. So he is not recommending Hebrew language proficiency so that one can make aliyah, something that did not exist in his day. He demands language study so that one can study Torah.

The Maharal also promoted study of grammar.