In addition to
@edumad you'll have time enough to get from Porto to Santiago.
Two possibilities to walk out of Porto. The coastal detour from Matosinhos. -take the metro to stop Mercado- on to Vila do Conde.
From there day 2 connection to the central route in São Pedro de Rates.
Other possibility. Take the metro in Porto to Forum Maia and walk from there to Mosteiro de Vairão and on to São Pedro de Rates.
From there can be your stops
Day 3 Barçelos
Day 4 casa Fernanda
Day 5 ponte de Lima
Day 6 Rubiaēs
Day 7 Valença do Minho or Tuí
Day 8 O Porriño
Day 9 Redondela or better Cessantes (Refuxio de la Jerézana is good albergue)
Day 10 Pontevedra
Day 11 caldas de Reis
Day 12 Padrón
Day 13 santiago
All distances between 15 and 20 kms per day
Only Padrón to Santiago is 24 kms but even that you could break by staying in Teo
The next day , the day of glorie entering Santiago is 8 kms by then and you can be early in Santiago eventually attending the pilgrims mass.
To speak portuguese or spanish is no need. There are so many international walkers that the population of both countries are used to speak english.
Non verbal language is international.
Bom caminho