At the beginning of the 20th century, between 1900 and 1905, the Galician thinker Ángel Amor Ruibal performs a synthesis of philological thought and historical grammar of Eastern and Western origins. He follows their development from the Middle Ages until the 19th century with the Comparative Grammar and deducts from it a continuous relationship between grammatical analysis (Egyptian, Sanskrit, Hebrew), symbolic specification of the voice (Chinese, American Indian languages) and logical synthesis (Greek, Latin). He recognizes also this synthetic and analytic relationship in the IndoEuropean as well as their survival in the romance derivation from Vulgar Latin. The analysis of the natural fact of language (languages) also reveals a psychological synthesis of material and human sound as realization of thought. Phonetic type is the constitutive form of root and etymology of words. Its organization reveals an relational and genetic principle which constitutes the first morph-syntactic units with its own semantic character: syllable, word, proposition. Amor Ruibal infers from this, before that Saussure, Sapir and other language specialists, the nature of the linguistic sign, its symbolic and rhetoric function. With these reflections he establishes the grounds of Linguistics in the 20th century, from structuralism, functionalism and generative theory of language to the textual grammar. The author of this article evaluates only part of this little-know theory of language and the linguistic precocity of his author. He concludes finally holding a poetic foundation of language.