The sentence that we usually think of when we think of Hunminjeongeum, which begins with "The language of the country is called 'Naratmalsami Bbaenggyeoldala'", also comes from here.
In other words, it is highly likely that Sejong did not actually say the words that begin with ‘National Language...’

The oldest version of Hunminjeongeum, included in the first edition of Wolinseokbo, Volume 1, dated 1459 and housed at Sogang University, is considered the most important source for Hunminjeongeum research.

There is the Hunminjeongeum Haeryebon (解例本), the original copy of the first edition published in the 28th year of King Sejong's reign (1446), and the Eonhaebon, which is an interpretation of the original in Hangul.
The extant translations include the following:

① The Korean version held by Sogang University: Published in the 5th year of King Sejo’s reign (1459).
② Korea University’s copy of the Korean version: Several parts have been supplemented in this single volume version.
③ Seoul National University copy: The manuscript is identical to the Sogang University copy.
It was originally a copy owned by the Japanese Imperial Household Ministry.
④ Sejong the Great Memorial Hall’s Eonhaebon: Engraved in the first year of King Seonjo’s reign (1568), this is a reprinted version owned by Huibangsa Temple.
Among the above-mentioned annotations, the most complete one is the one owned by Sogang University. This is not a single volume, but is included in the first volume of Wolinseokbo (1459). The book is titled Sejong Eoje Hunminjeongeum (世宗御製 訓民正音), and is a woodblock edition printed with woodblocks.
Among the Korean fonts in this book, the large letters are displayed more smoothly than those in the Haeryebon.
In other words, the thickness of the large letters' strokes was changed, and the stroke direction of the strokes was also horizontal.
perpendicular.
It is expressed at various angles rather than symmetrically, giving the impression that it was written directly with a brush.