1. A method for configuring a speech recognition system, the method comprising: obtaining a speech sample from a user utilised to authenticate the user as part of an authentication process; processing the speech sample to train one or more generic acoustic model(s) for units of speech associated with the speech sample; storing the trained acoustic model(s) in a personalised acoustic model set for the user; selectively re-training the acoustic model(s) in the personalised model set based on additional speech samples provided by the user containing corresponding units of speech; responsive to determining that the user has accessed a speech recognition function, directing a speech recognition process to access the personalised model set for recognising subsequent user utterances; and further comprising determining a measure of quality for each of the stored acoustic models and wherein the acoustic modules are re-trained based on additional speech samples until the corresponding quality measure meets a predefined threshold.