Who changed the block flute to the word recorder?

Answer 1

No one, really.

The term "recording" was old English for the kind of song that birds produce. The term "block Flute" is a modern, weak translation of "Blockfluit" which is properly called "fipple flute" to differentiate it from the traverse flutes.

In short, you have a doublehandful of semi-technical terms which have been used by instrument makers, instrumentalists, musicologists and modern musicians without much specificity.

Maybe this will help:

In the Renaissance, the English referred to the transverse-type of flute as Piffaro (we're not sure why yet) and this is the way Queen Elizabeth I referred to her favorite group of instruments. They were played by town guards, military unit bands (which weren't called bands) and professional musicians in the Royal chamber, but were considered largely a military sound. The recorders were called "flute" or if there was doubt whether recorders or "german"(transverse) flute (which were called "flauto traverse" or "German flute") were in view.

In the Baroque period which followed, the recorder was only referred to as "Flute". That means every time you see "Flute" in an original print or manuscript, it meant recorder, most often the Alto (treble) size... although even there, it is not always obvious without observing the notes used and the keys employed: Our modern Alto is a beast of convenience. The usual keys of recorders were F bass, C tenor, G alto and d soprano. (Identifying sizes of instruments through this period is _not_ a simple process, since pitches were not standardized to frequencies as they are today.) If what we now call "flute" was wanted, it was always specified as "Flauto Traverso" or "German Flute". Variations in spelling clouded the issue only slightly, as did spelling based on different European languages.

The term "Block Flute" refers to every kind of 'pipe' which is sounded by the fipple arrangement, including organ flue pipes. It is a technical descriptive, rather than an historically-used common term. It applies to pennywhistles, recorders, organ pipes of a certain variety, flageolets, and anything else which forms a windway with a block of material, or which ends up working that way.