Bircas Tefillin Shel Rosh for an Ashkenazi
Some berachot have a prefix of 'al' as in 'Al Hamilah' i.e. Only a certain person can perfom the milah. As opposed to "L"hadlik' i.e, anyone can do it.-------The problem arises with an ashkenazi man donning Tefilin. First blesing has "L" i.e. 'L'haneeach', the second has "Al' i,e "Mitzvat tefillin'----Is there a problem ??
To the Questioner,
From the Talmud Yerushalmi (Brachot 91a) we can understand that the difference in the two forms of brachot is: "L" is said regarding an obligation incumbent on a person; "Al" is said when the obligation is not incumbent on a person.
According to this we can understand the wordings of the berachot:
The mitzva of milah is that every Jewish male should live with a body which had its "orlah" already removed. Thus the real obligation of the mitzva is incumbent upon the person being circumcised. Since the Torah says that a child needs to be circumcised from when he is only eight days after birth, it is clear that in the overwhelming majority of cases the child will not be the one to perform the circumcision on himself - someone else will. When that someone else approaches the circumcision and makes a bracha, he needs to say "Al" - because the mitzva is not incumbent upon him.
In contrast, regarding tefillin, the person making the bracha and doing the mitzva, is the one who the obligation of the mitzva is incumbent upon. He must therefore say "L".
In regard to Tefillin Shel Rosh (the tefillin placed on the head), there is a separate reason as to why the wording of “Al” is used. Tosfot explain, (Brachot 60b, piece beginning asher kidishanu) that the reason for the difference in wording of the Tefillin Shel Rosh from the Tefillin Shel Yad (the tefilllin placed on the hand) is because “he already began and did the act of hanachah (placing) for one of the tefillin”. In other words, even though the two tefillins are recognized as two separate mitzvot (Rambam, Sefer Hamitzvot, Aseh 12-13) and they are both incumbent upon a person [so therefore the bracha should seemingly be “L” for both], we do not say “L” for the Shel Rosh, because it is inappropriate to use the wording “you have commanded us to place the tefillin”, which implies in Hebrew that he is just beginning to do the act of placing, when he has already done it and is not beginning the act right now.
Therefore an Ashkenazi who follows the opinion of Rabbenu Tam (Tosfos ibid) does not have a problem whatsoever to pronounce the first bracha on the tefillin with “L” and the second with “Al”.