Having assessed the various explanations, the first documents from previous studies and questions of orality and writing in the language's initial stages, the second part of the study (II) of Latin's initial /f/ sound weakening to (h) in that period provides a selection ofa documentary corpus from the VIII to the XII century, which has a geographical span also related to the Basque language in Castille and La Rioja. U7e present the results from an analysis over 200 words with all their variants in which there are orthographic differences which involve the graphemes <f> and <h> in all their positions in a word. We examine the possible direct or indirect indicators ofphonetic change. The data is included in the last section of the study along with some considerations about its oral and written character, to finish with the conclusions which highlight the relationship ofsome of the issues we have raised with the Basque language.