"A time to keep silent and a time to speak." (Ecclesiastes 3:7)
"These are the descendants of Noah: Noah was a righteous man, wholesome in his generations. Noah walked with God." (Genesis 6:9)
With these words, the Torah introduces us to the man who would save humanity from
In whose generations could he be righteous and wholesome if not in his own?
total annihilation in the Flood. In the previous verse (the concluding verse of parashat Bereshit), the Torah informs us that "Noah found favour in the eyes of HaShem."

In whose generations could he be righteous and wholesome if not in his own?
total annihilation in the Flood. In the previous verse (the concluding verse of parashat Bereshit), the Torah informs us that "Noah found favour in the eyes of HaShem."The Talmud (Sanhedrin 108a) records two contradictory opinions of why the Torah adds in the seemingly superfluous word b'dorotav ("in his generations"). After all, in whose generations could he be righteous and wholesome if not in his own? Rabbi Yochanan interprets this as denigrating Noah: compared to his generations - the generations of idolatry and violent robbery - he was righteous; in normal generations he would not have stood out. Reish Lakish takes the opposite view, interpreting it as praising Noah: even in his generations, with all the all-pervasive negative influence surrounding him since birth, he still remained righteous; how much more righteous would he have been had he lived in normal generations.
Both explanations are logical, and Rabbi Shimshon Raphael Hirsch synthesises them: Noah's constant struggle against the evil influences around him must have weakened him spiritually to some extent, but together with this, any degree of righteousness in such evil surroundings is worth far more than greater righteousness in better times.
Nonetheless, Rabbi Yochanan's view needs some explaining. Since the Torah states explicitly that "Noah was a righteous man, wholesome," why does Rabbi Yochanan seek to find some hint that he was anything less? Indeed, the major commentators find nothing but praise:
"'In his generations' – [he was righteous] both in the generation of the flood and in the subsequent generations, because he lived until Abraham was 58 years old." (Ibn Ezra)
"In my opinion, the correct explanation according to the simple meaning is that he was the only tzaddik in those generations; there was no one who was righteous, no one who was wholesome apart from him." (Ramban)
Where does the Torah give any hint that Noah was anything less than perfect?
When God told Noah to start building the Ark (6:13ff), He granted Noah - and the entire world - a period of grace of 120 years before the flood would come upon the Earth 
The major commentators find nothing but praise.
(Targum Yonatan to Genesis 6:3; Numbers Rabbah 14:12; Sifrei, Deuteronomy 43, et. al.; see also Rashi to Genesis 6:3). During this 120-year period, while building the Ark, Noah's charge was to alert all mankind to its impending destruction, and to do all he could to convince them to repent. For this reason, he built the Ark in the midst of the continent, far from any seashore, precisely in order to arouse the curiosity of all who would see him, and provide him with the opportunity to explain and persuade. In this respect, however, Noah failed: apart from his own immediate family, he did not manage to save a single person in the entire world.

The major commentators find nothing but praise.
(Targum Yonatan to Genesis 6:3; Numbers Rabbah 14:12; Sifrei, Deuteronomy 43, et. al.; see also Rashi to Genesis 6:3). During this 120-year period, while building the Ark, Noah's charge was to alert all mankind to its impending destruction, and to do all he could to convince them to repent. For this reason, he built the Ark in the midst of the continent, far from any seashore, precisely in order to arouse the curiosity of all who would see him, and provide him with the opportunity to explain and persuade. In this respect, however, Noah failed: apart from his own immediate family, he did not manage to save a single person in the entire world. Commensurate with this, throughout the 91 verses that relate Noah's life - his birth (5:28), the birth of his three sons, the degeneration of humanity, the warning of the impending flood, the building of the Ark, the ingathering of the animals, the one year spent on the Ark, sending out the raven and subsequently the dove to discover if there was yet any dry land, leaving the Ark, offering sacrifices to God, receiving God's blessings, beginning to repopulate the world - nowhere do we find that Noah ever speaks. The phrase, "And Noah said..." is blatantly absent from the entire narrative.
This is in stark contrast to our father Abraham, ten generations later. Abraham brought the knowledge of the One God to masses of people; and when God told him of the impending destruction of Sodom and Gomorrah, Abraham protested, interceding for the tzaddikim of that metropolis. (True, there were no such tzaddikim - but Abraham did not know this at the time.) And 400 years later, when God threatened to exterminate the whole of Israel for the sin of the Golden Calf, "Moshe pleaded before HaShem his God, saying: 'Why, O HaShem, does Your fury flare up against Your Nation?...Relent from Your flaming fury and reconsider the evil against Your nation.'" (Exodus 32:11-12) Surely, it would have appropriate for Noah to have similarly protested when God spoke of destroying the whole of humanity.
To be sure, Noah does all that God commands him, but he is totally passive, never taking initiative.
The first time that Noah does take his own initiative, and the first time that he opens his mouth to speak, is long after the flood had finished: "Noah began to be a man of the earth, and he planted a vineyard; he drank from the wine and got drunk.... Ham, the father of Canaan, saw his father's nakedness and told his two brothers outside. Shem and Japheth took the cloak, put it on both their shoulders, and walked backwards to cover their father's nakedness.... When Noah awoke from his wine, he knew what his youngest son had done to him, and he said: 'Accursed be Canaan; he will be a slave of slaves to his brothers.'" (9:21-25)
These are the first words that the Torah records Noah as ever having spoken. To be sure, this curse was appropriate; but it was not appropriate for a tzaddik to use the word "accursed" as his first utterance. It would have been far more appropriate for Noah to start with, "Blessed be HaShem, the God of Shem" (which he only says in the next verse).
This casts an interesting light on the midrashic observation: "God used circumlocution in two or three places in the Torah in order not to use impure language. The verse says, 'From every clean animal take for yourself seven males and females of each' (Genesis 7:2); it does not [then] say, 'And from the animal which is unclean, two - male and female,' but rather '...the animal which is not clean.'" (Genesis Rabbah 32:4)
The prevalent evil that condemned the world began with impure speech, and degenerated from impure speech to sexual immorality and violence; and the tikkun in this specific context is such that the Torah does not even mention the word t'mei'ah ("unclean") to describe the animals, using instead the more cumbersome lo tehorah ("not clean").
It is perhaps significant that this midrashic observation is made by Rabbi Yudan, who was quoting his predecessor, Rabbi Yochanan - the same Rabbi Yochanan who had interpreted the term b'dorotav ("in his generations") as denigrating Noah. (To put this into historical context, Rabbi Yudan was the student of Rabbi Abba, who in turn had studied from Rabbi Avahu, who was one of Rabbi Yochanan's outstanding students.)
Rebbe Nachman of Breslov observed that the dimensions of Noah's Ark were 300 cubits by 50 cubits by 30 cubits (6:15), represented by the letters lamed, shin, nun - the letters which spell the word lashon ("tongue, speech, language"). The Ark came to rectify the evil that began with bad speech.
It is also noteworthy that the Hebrew word teivah means both "ark" and "word": the purpose of the teivah of Noah was to rectify the evil caused by the foul teivah that had become so prevalent in the world.
And it is surely no coincidence that when, 340 years after the flood (according to Seder Olam), the people of Shinar decided to rebel against God by building the Tower of Babel 
Nowhere do we find that Noah ever speaks.
(Genesis 11), the Torah introduces the subject by telling us that "the entire world spoke one language." And God put an end to their plans of world domination by "confound[ing] their language, so that they will no longer understand each man his fellow's language." (v. 7)

Nowhere do we find that Noah ever speaks.
(Genesis 11), the Torah introduces the subject by telling us that "the entire world spoke one language." And God put an end to their plans of world domination by "confound[ing] their language, so that they will no longer understand each man his fellow's language." (v. 7)Language is what sets man apart from the animals; indeed, the word medaber ("that which speaks") is one of the Hebrew synonyms for "human". God has given us the power of speech, and it is up to us to know how to use it to sanctify the world, not to desecrate it; to elevate ourselves, not to degrade ourselves; to bless, and not to curse; and - in the words of King Solomon - to discern between "a time to keep silent and a time to speak." (Ecclesiastes 3:7)