Shabbat Vayhi

And he said, bring them to me so that I may bless them. ... And he placed Ephraim before Menashe.
Was not Jacob repeating the mistake of singling out two grandchildren from among the many, as he did with Yosef and his brothers? Secondly, was he not creating jealousy between Menashe and Ephraim?

Harav Yaakov Kametetzky, Z"L posits that Yaakov sons were acutely aware of the fact that Yosef's children, having been raised in the moral filth of Egypt would need an extra blessing. They neither saw the beauty nor experienced the holiness and purity that permeated Yaakov's home This is suggested by the fact that no one seemed concerned when Yaakov singled out Yosef's sons for a blessing, something he had not done for any of his other grandchildren.

With this in mind, we understand why Yaakov mentioned Ephraim's name before that of Menashe. Efraim needed the blessing more. Menashe was born first. At that time Yosef still remembered his father's home. It still exercised a strong effect on him. Indeed, the name Menashe implies, "It made forget". In other words, when Menashe was born, the memories of home, although bitterweet, were still present. When Ephraim was born, Yosef viewed himself to be more of a citizen of Egypt. He was already moving in the circles of power. Indeed, as Rav Yaakov notes, the average Egyptian name was usually comprised of the letters, Pe, Resh,Ayin, which were the letters of Pharao's name.
Ephraim's name was comprised of these same letters, indicating a greater affinity to Egyptian society and its way of life. Perhaps this is why Ephraim studied with Yaakov, more than Menashe, since Menashe knew the Hebrew language, while Ephraim might not have been as fluent. In essence, since Menashe and Ephraim were born and raised in Egypt, they needed extra spiritual care . Everyone acknowledged this perspective.