Corrected spelling mistakes.

doc/extending/ctype.txt

@@ -130,7 +130,7 @@ associated to the Variable is ``py_<name>``.
 suitable for use in certain situations. For instance, ``sub['fail']``
 contains code that should be inserted wherever an error is identified.
 
-``c_declare`` and ``c_extract`` also takes a third ``check_input`` 
+``c_declare`` and ``c_extract`` also accept a third ``check_input`` 
 optional argument. If you want your type to validate its inputs, it must
 do it only when ``check_input`` is True.
 

doc/tutorial/extending_theano.txt

@@ -135,7 +135,7 @@ string representation of your op.
 The :func:`R_op` method is needed if you want ``theano.tensor.Rop`` to
 work with your op.
 
-The optionnal boolean :func:'check_input' attribute is used to specify if you want the types used in 
+The optional boolean :func:'check_input' attribute is used to specify if you want the types used in 
 your op to check their inputs in their c_code. It can be used to speed up compilation and reduce the 
 number of generated c_file.