If you want to add the translation in your language try to keep at least the number of the english word, so you don't have to write it again - for new words, keep adding numbers. (for example: 16. gr/dt Feuerblitz)
I think, the easiest way to find the terms is to use the search menu on the explorer window (ctrl+F, for example).
Feel free to make any corrections!
If you ask yourselves what's the goal of this dictionary: I think it is a help for those, who don't know what a particular word means or how they have to translate the word in english, because they didn't read the books in english. On the other hand, you can always learn some words in other languages, thats fun for some people, I think
It is not a problem if you only add one or two words, because everybody might find them by searching the original english word or the corresponding number.
1. Baron, the Bloody
 	sp. El Varón Sanguinario
2. Beater
 	sp. bateador
3. Bertie Bott's Every Flavor Beans
 sp. grageas Bertie Bott de Todos los Sabores
4. Blast-ended screwts
 	sp. Escregutos de cola explosiva
5. Bubotubers
 	sp. bubotubérculos
6. Canary cream
 sp. galleta de canario
7. Chaser
 sp. cazador
8. Chocolate frogs
 sp. ranas de chocolate
9. Curse
 sp. maldición
10. Daily Prophet
 sp. periódico/diario El Profeta
11. Dark Mark
 sp. Marca tenebrosa
12. Death Eaters
 sp. mortífagos
13. Diagon Alley
 			sp. callejón Diagon
14. Fat Friar
 		sp. Fraile Gordo
15. Fat Lady
 		sp. Dama Gorda
16. Firebolt
 		sp. Saeta de Fuego
17. Floo Powder/Network
 		sp. polvos/red de polvos Flu
18. Foe-Glass
 		sp. detector de enemigos
19. Forbidden Forest
 		sp. Bosque prohibido
20. Gillyweed
 		sp. branquialgas
21. Goblet of fire
 		sp. Cáliz de fuego
22. Grey Lady
 		sp. Dama Gris
23. House elf
 		sp. elfo doméstico
24. Howler
 		sp. vociferador
25. Invisibility cloak
 		sp. capa de invisibilidad
26. Keeper
 	sp. portero
27. Knight Bus
 		sp. autobus Noctámbulo
28. The Leaky Cauldron
 		sp. El Caldero Chorreante
29. Mandrake
 		sp. mandrágora
30. Marauder's Map
 		sp. Mapa del Merodeador
31. Moaning Mirtle
 		sp. Mirtle la Llorona
32. Mudblood
 		sp. Sangre sucia
33. St Mungo's Hospital for Magical Maladies and Injuries
 sp. Hospital San Mungo de Enfermedades y heridas Mágicas
34. Nick Nearly Headless
 	sp. Nick Casidecapitado
35. O.W.L.s /owl
 	sp. TIMOS /lechuza
36. Pensieve
 	sp. pensadero
37. Pocket sneakoscope
 	sp. chivatoscopio
38. Polyjuice potion
 	sp. poción multijugos
39. Portkey
 	sp. traslador
40. Quick-quotes quill
 	sp. pluma vuelapluma
41. Remembrall
 	sp. recordadora
42. Secrecy Sensor
 	sp. Sensor de ocultamiento
43. Seeker
 sp. buscador
44. Shrieking Shack
 	sp. casa del los gritos
45. Sorcerer's Stone
 	sp. piedra filosofal
46. Sorting Hat
 	sp. Sombrero seleccionador
47. S.P.E.W.
 	sp. PEDDO
48. The Three Broomsticks
 	sp. Las Tres Escobas
49. Ton-Tongue Toffee
 	sp. Caramelo Longuilinguo
50. Unforgiveable Curses
 	sp. Maldiciones Imperdonables
51. Wormtail
 	sp. Colagusano
If anyone knows if it's possible to put an excel like grid on a post, please tell me. (TABs didn't work, so I put
 between the words)
 Its brill!