If a customer calls their bank in Basque and the agent does not understand the language, what happens? Until now, financial sector regulation required institutions to respond to written complaints in the same language in which they had been submitted. It was a limited right and relatively easy to manage. Law 10/2025 significantly expands this right, with much broader practical implications for customer service teams.
This is currently one of the areas with the highest level of interpretative ambiguity, but precisely for that reason it deserves detailed analysis: financial institutions need guidance in order to start taking action.
What Already Existed: The Right to Receive a Response in the Language of the Complaint
Sector-specific regulation already established that customers have the right to submit complaints in Spanish or in any co-official language of the territory where they reside (Catalan, Basque, Galician, or Valencian) and to receive the response in that same language. This right applied to formal written complaints managed under the regulatory framework supervised by the Bank of Spain, the CNMV, and the DGSFP.
To manage this requirement, many institutions relied on specialized teams or translation services. The volume was manageable because it was limited to a specific type of communication.
What the Customer Service Law Adds: Language Throughout the Entire Interaction
Law 10/2025 goes much further. Its approach is that linguistic criteria should not be limited to formal complaints: they must apply to the entire interaction with the Customer Service department, including phone calls, live chats, emails, messaging services, and any other communication channel.
If an institution operates in a territory with a co-official language, it must be able to assist and respond in that language whenever requested by the customer, both orally and in writing. Customer service teams must also be trained accordingly.
Articles 29 ter.2 and 29 septies.4 of the amended Law 44/2002 establish this linguistic framework. The regulation does not state that every call must be handled in a co-official language. It states that when a customer requests it, the institution must be able to respond. But that “must be able to” carries very specific organizational implications.
The Operational Challenge: People, Training, and Availability
Having agents capable of providing fluent support in Catalan, Basque, Galician, and Valencian across all shifts and all channels is not easy, especially for medium-sized institutions or national organizations whose customer service centers are located in a single site.
The market for professionals fluent in some of these languages (particularly Basque) is limited. Geographic dispersion of customers adds further complexity: an institution may simultaneously serve customers in the Basque Country, Catalonia, and Galicia, each with different language needs during the same working shift.
The law does not establish specific availability thresholds, but this does not exempt institutions from compliance. What it does require is a structural customer service model, not merely occasional solutions.
Can Technology Be the Solution?
The answer is nuanced but encouraging. The law does not rule out the use of language assistance technology or AI-powered real-time translation systems, provided that service quality is guaranteed. This opens the door to real-time support tools for agents who do not fully master the language: systems capable of transcribing and translating conversations, allowing agents to understand customers and respond coherently.
However, technology does not eliminate responsibility for service quality. If the system makes translation errors that affect the proper resolution of the request, responsibility still lies with the institution. In addition, the system must be auditable.
Callback as a Temporary Solution, Not a Structural One
If, at a specific moment, no agent is available in the requested language, offering a callback from a qualified agent may be a valid solution. But with the same limitations applicable to waiting-time KPIs: it cannot become the standard approach. The institution must be able to demonstrate that it has a structural model for providing support in co-official languages, and that callbacks are only used exceptionally.
The Risk of Inaction
Co-official languages are considered a high-priority issue by Consumer Protection Authorities, especially in Catalonia, the Basque Country, and Galicia. The likelihood of receiving a complaint or undergoing an inspection in this area is higher than for many other regulatory requirements, partly because it is a right that citizens know and value, and partly because it is relatively easy for inspectors to verify whether an institution can provide service in a co-official language.
Institutions operating in these territories should include this issue in their compliance risk map and develop an action plan supported by documented evidence: who provides support in each language, what training agents have received, how demand is managed when immediate availability is not possible, and what technology is used as support.
Consulting C3 and MST Holding actively participate in the UNE Committee responsible for defining the audit standard for the Customer Service Law and maintain ongoing contact with the AERC to communicate the sector’s concerns to the organizations responsible for clarifying them.