It is possible to learn Spanish in 15 days. To do this, you can start learning Spanish by memorizing the most commonly used phrases in Spanish and the most frequently used Spanish words. It will also be very useful to practice speaking Spanish, writing down what you have learned
, reading it aloud and repeating it.
To improve your pronunciation, learn the Spanish alphabet and listen to pronunciation examples from useful foreign language apps such as reverso context, spanish.dict and wordreference. Don't worry about grammar in the early days.