The Gemara (Berachot 11b) brings three different opinions among the Amora'im regarding the text of Birkot Ha'Torah – the blessing recited each morning over Torah study. The accepted Halacha is to recite all three of these blessings, and they together comprise the series of Berachot known to us as Birkot Ha'Torah.
These three blessings are:
"Baruch… Asher Kideshanu Be'misvotav Ve'sivanu Al Dibreh Torah."
"Ve'ha'areb Na…"
"Baruch…Asher Bahar Banu MI'kol Ha'amim…"
The conclusion of the first of these blessings, as cited here, is "Al Dibreh Torah," which reflects the Sephardic custom. Askhenazic practice is to conclude the Beracha with the words "La'asok Be'dibreh Torah" – "to engage in the words of Torah." This was the text used by the Jews of France and Provence, and has been accepted by Ashkenazic communities.
The advantage of this text is that it speaks of the act of Torah study, which, seemingly, is what this Beracha is all about. Moreover, as the Rabbis of Mussar have discussed at length, the word "La'asok" connotes passion, vigor, and intensive engagement. Indeed, in modern Hebrew, a business is called an "Esek," because it is what a person devotes most of his time, attention and energy to. Torah is our primary "business," our most important "occupation," the focal point of our lives, around which everything else is to revolve. And thus the expression "La'asok Be'dibreh Torah" is an appropriate text for the blessing in which we thank Hashem for the precious Misva of Torah learning.
The Rambam's text of this Beracha, however, is "Al Dibreh Torah," which means – "regarding the words of Torah." The Sefer Ha'manhig (Rav Abraham Ben Natan, Provence, d. 1215) writes that this was the prevalent text in Spain. He notes that unlike "La'asok Be'dibreh Torah," which speaks specifically of the Misva to learn Torah, the text "Al Dibreh Torah" is more generic, encompassing all the other Misvot. The Yafeh La'leb (Rav Rahamim Nissim Yishak Palachi, Turkey, 1813-1907) explains that with the text of "Al Dibreh Torah," this Beracha covers all the Misvot that we observe throughout the day for which no Beracha is recited. Hazal instituted the recitation of a Beracha before the performance of certain Misvot, such as Tefillin, Sisit, hand-washing before bread, and lighting Shabbat candles, but many Misvot that we perform are not introduced with a blessing. Thus, for example, we do not recite a Beracha before giving charity to a needy person, or before assisting a parent (in fulfillment of the Misva of Kibbud Ab Va'em – honoring parents). Therefore, we recite the Beracha of "Al Dibreh Torah" to cover all Misvot for which there is no blessing.
It must be clarified, however, that even according to this understanding of the text of the Beracha, one is allowed to perform Misvot before reciting Birkot Ha'Torah in the morning. Although the phrase "Al Dibreh Torah" might refer to Torah learning and also all other Misvot that will be performed over the course of the day, only Torah learning is forbidden before the recitation of Birkot Ha'Torah, and not other Misvot. Thus, for example, one is allowed to help his parents before reciting Birkot Ha'Torah morning, and to give Sedaka. This is the ruling of Hacham Ovadia Yosef.