If you're asking which Panamanian cities speak Spanish, the answer is simple: all of them. Spanish is Panama's sole official language and the mother tongue of over 90% of the population. It's the language of government, education, media, commerce, and daily life from the Darién Gap to the Costa Rican border.
Panamanian Spanish has distinctive features: voseo (using vos instead of tú in some regions), Caribbean-influenced pronunciation (aspirated /s/, dropped final consonants), and vocabulary enriched by English (from the Canal Zone era), indigenous languages (Ngäbere, Buglé, Kuna), and Afro-Antillean communities.
Minority languages exist but are community-specific: Ngäbere and Buglé (Ngäbe-Buglé comarca), Kuna (Guna Yala), Emberá/Wounaan (Darién), and English-based Creole in Bocas del Toro and Colón. Chinese (Cantonese, Hakka, Mandarin) and Arabic (Lebanese/Syrian heritage) are spoken in commercial communities. But Spanish remains the universal bridge.
For visitors: Spanish is essential outside tourist zones. English proficiency varies—high in Panama City's business/hospitality sectors, low elsewhere. A few phrases (¿Cuánto cuesta?, ¿Dónde está...?, La cuenta, por favor) go a long way.