To say where you are from: "I'm from Spain" or "I'm Spanish". Nationalities are adjectives — always start with a capital letter in English (Spanish, French, Italian…).
Algeria
/ælˈdʒɪə.ri.ə/
She is Algerian.
Angola
/æŋˈɡəʊ.lə/
He is Angolan.
Benin
/beˈniːn/
She is Beninese.
Botswana
/bɒtˈswɑː.nə/
He is Botswanan.
Burkina Faso
/bɜːˌkiː.nə ˈfæs.əʊ/
She is Burkinabe.
Burundi
/bʊˈrʊn.di/
He is Burundian.
Cabo Verde
/ˌkɑː.bəʊ ˈvɜː.di/
She is Cape Verdean.
Cameroon
/ˌkæm.əˈruːn/
He is Cameroonian.
Central African Republic
/ˌsen.trəl ˈæf.rɪ.kən rɪˈpʌb.lɪk/
She is Central African.
Chad
/tʃæd/
He is Chadian.
Comoros
/ˈkɒm.ə.rəʊz/
She is Comoran.
Republic of the Congo
/rɪˌpʌb.lɪk əv ðə ˈkɒŋ.ɡəʊ/
He is Congolese.
DR Congo
/ˌdiː ˈɑːr ˈkɒŋ.ɡəʊ/
She is Congolese.
Djibouti
/dʒɪˈbuː.ti/
He is Djiboutian.
Egypt
/ˈiː.dʒɪpt/
She is Egyptian.
Equatorial Guinea
/ˌek.wəˌtɔː.ri.əl ˈɡɪn.i/
He is Equatorial Guinean.
Eritrea
/ˌer.ɪˈtreɪ.ə/
She is Eritrean.
Eswatini
/ˌes.wɑːˈtiː.ni/
He is Swazi.
Ethiopia
/ˌiː.θiˈəʊ.pi.ə/
She is Ethiopian.
Gabon
/ɡæˈbɒn/
He is Gabonese.
Gambia
/ˈɡæm.bi.ə/
She is Gambian.
Ghana
/ˈɡɑː.nə/
He is Ghanaian.
Guinea
/ˈɡɪn.i/
She is Guinean.
Guinea-Bissau
/ˌɡɪn.i bɪˈsaʊ/
He is Bissau-Guinean.
Ivory Coast
/ˌaɪ.vər.i ˈkəʊst/
She is Ivorian.
Kenya
/ˈken.jə/
He is Kenyan.
Lesotho
/ləˈsuː.tuː/
She is Basotho.
Liberia
/laɪˈbɪə.ri.ə/
He is Liberian.
Libya
/ˈlɪb.i.ə/
She is Libyan.
Madagascar
/ˌmæd.əˈɡæs.kər/
He is Malagasy.
Malawi
/məˈlɑː.wi/
She is Malawian.
Mali
/ˈmɑː.li/
He is Malian.
Mauritania
/ˌmɒr.ɪˈteɪ.ni.ə/
She is Mauritanian.
Mauritius
/məˈrɪʃ.əs/
He is Mauritian.
Morocco
/məˈrɒk.əʊ/
She is Moroccan.
Mozambique
/ˌməʊ.zæmˈbiːk/
He is Mozambican.
Namibia
/nəˈmɪb.i.ə/
She is Namibian.
Niger
/niːˈʒeər/
He is Nigerien.
Nigeria
/naɪˈdʒɪə.ri.ə/
She is Nigerian.
Rwanda
/ruˈæn.də/
He is Rwandan.
Sao Tome and Principe
/ˌsaʊ təˌmeɪ ənd ˈprɪn.sɪ.peɪ/
She is Sao Tomean.
Senegal
/ˌsen.ɪˈɡɔːl/
He is Senegalese.
Seychelles
/seɪˈʃelz/
She is Seychellois.
Sierra Leone
/siˌer.ə liˈəʊn/
He is Sierra Leonean.
Somalia
/səˈmɑː.li.ə/
She is Somali.
South Africa
/saʊθ ˈæf.rɪ.kə/
He is South African.
South Sudan
/saʊθ suːˈdɑːn/
She is South Sudanese.
Sudan
/suːˈdɑːn/
He is Sudanese.
Tanzania
/ˌtæn.zəˈniː.ə/
She is Tanzanian.
Togo
/ˈtəʊ.ɡəʊ/
He is Togolese.
Tunisia
/tjuːˈnɪz.i.ə/
She is Tunisian.
Uganda
/juːˈɡæn.də/
He is Ugandan.
Zambia
/ˈzæm.bi.ə/
She is Zambian.
Zimbabwe
/zɪmˈbɑːb.weɪ/
He is Zimbabwean.
Afghanistan
/æfˈɡæn.ɪ.stæn/
She is Afghan.
Armenia
/ɑːˈmiː.ni.ə/
He is Armenian.
Azerbaijan
/ˌæz.ər.baɪˈdʒɑːn/
She is Azerbaijani.
Bahrain
/bɑːˈreɪn/
He is Bahraini.
Bangladesh
/ˌbæŋ.ɡləˈdeʃ/
She is Bangladeshi.
Bhutan
/buːˈtɑːn/
He is Bhutanese.
Brunei
/bruːˈnaɪ/
She is Bruneian.
Cambodia
/kæmˈbəʊ.di.ə/
He is Cambodian.
China
/ˈtʃaɪ.nə/
She is Chinese.
Georgia
/ˈdʒɔː.dʒə/
He is Georgian.
India
/ˈɪn.di.ə/
She is Indian.
Indonesia
/ˌɪn.dəˈniː.ʒə/
He is Indonesian.
Iran
/ɪˈrɑːn/
She is Iranian.
Iraq
/ɪˈrɑːk/
He is Iraqi.
Israel
/ˈɪz.reɪ.əl/
She is Israeli.
Japan
/dʒəˈpæn/
He is Japanese.
Jordan
/ˈdʒɔː.dən/
She is Jordanian.
Kazakhstan
/ˌkæz.ækˈstɑːn/
He is Kazakh.
Kuwait
/kʊˈweɪt/
She is Kuwaiti.
Kyrgyzstan
/ˌkɪər.ɡɪˈstɑːn/
He is Kyrgyz.
Laos
/laʊs/
She is Laotian.
Lebanon
/ˈleb.ə.nən/
He is Lebanese.
Malaysia
/məˈleɪ.ʒə/
She is Malaysian.
Maldives
/ˈmɔːl.diːvz/
He is Maldivian.
Mongolia
/mɒŋˈɡəʊ.li.ə/
She is Mongolian.
Myanmar
/ˈmjæn.mɑː/
He is Burmese.
Nepal
/nɪˈpɔːl/
She is Nepali.
North Korea
/nɔːθ kəˈrɪə/
He is North Korean.
Oman
/əʊˈmɑːn/
She is Omani.
Pakistan
/ˈpɑːk.ɪ.stɑːn/
He is Pakistani.
Palestine
/ˈpæl.ə.staɪn/
She is Palestinian.
Philippines
/ˈfɪl.ɪ.piːnz/
He is Filipino.
Qatar
/ˈkʌt.ər/
She is Qatari.
Saudi Arabia
/ˌsaʊ.di əˈreɪ.bi.ə/
He is Saudi.
Singapore
/ˈsɪŋ.ə.pɔːr/
She is Singaporean.
South Korea
/saʊθ kəˈrɪə/
He is South Korean.
Sri Lanka
/ˌsriː ˈlæŋ.kə/
She is Sri Lankan.
Syria
/ˈsɪr.i.ə/
He is Syrian.
Tajikistan
/tɑːˌdʒiː.kɪˈstɑːn/
She is Tajik.
Thailand
/ˈtaɪ.lænd/
He is Thai.
Timor-Leste
/ˌtiː.mɔː ˈles.teɪ/
She is Timorese.
Turkey
/ˈtɜː.ki/
He is Turkish.
Turkmenistan
/tɜːkˌmen.ɪˈstɑːn/
She is Turkmen.
United Arab Emirates
/juˌnaɪ.tɪd ˈær.əb ˈem.ɪ.rəts/
He is Emirati.
Uzbekistan
/ʊzˌbek.ɪˈstɑːn/
She is Uzbek.
Vietnam
/ˌvjetˈnæm/
He is Vietnamese.
Yemen
/ˈjem.ən/
She is Yemeni.
Albania
/ælˈbeɪ.ni.ə/
She is Albanian.
Andorra
/ænˈdɔːr.ə/
He is Andorran.
Austria
/ˈɒs.tri.ə/
She is Austrian.
Belarus
/ˌbel.əˈruːs/
He is Belarusian.
Belgium
/ˈbel.dʒəm/
She is Belgian.
Bosnia and Herzegovina
/ˌbɒz.ni.ə ənd ˌhɜːt.sɪ.ɡəʊˈviː.nə/
He is Bosnian.
Bulgaria
/bʌlˈɡeə.ri.ə/
She is Bulgarian.
Croatia
/krəʊˈeɪ.ʃə/
He is Croatian.
Cyprus
/ˈsaɪ.prəs/
She is Cypriot.
Czechia
/ˈtʃek.i.ə/
He is Czech.
Denmark
/ˈden.mɑːk/
She is Danish.
Estonia
/eˈstəʊ.ni.ə/
He is Estonian.
Finland
/ˈfɪn.lənd/
She is Finnish.
France
/frɑːns/
He is French.
Germany
/ˈdʒɜː.mə.ni/
She is German.
Greece
/ɡriːs/
He is Greek.
Hungary
/ˈhʌŋ.ɡər.i/
She is Hungarian.
Iceland
/ˈaɪs.lənd/
He is Icelandic.
Ireland
/ˈaɪə.lənd/
She is Irish.
Italy
/ˈɪt.ə.li/
He is Italian.
Latvia
/ˈlæt.vi.ə/
She is Latvian.
Liechtenstein
/ˈlɪk.tən.staɪn/
He is Liechtensteiner.
Lithuania
/ˌlɪθ.juˈeɪ.ni.ə/
She is Lithuanian.
Luxembourg
/ˈlʌk.səm.bɜːɡ/
He is Luxembourgish.
Malta
/ˈmɒl.tə/
She is Maltese.
Moldova
/mɒlˈdəʊ.və/
He is Moldovan.
Monaco
/ˈmɒn.ə.kəʊ/
She is Monegasque.
Montenegro
/ˌmɒn.tɪˈniː.ɡrəʊ/
He is Montenegrin.
Netherlands
/ˈneð.ə.ləndz/
She is Dutch.
North Macedonia
/nɔːθ ˌmæs.ɪˈdəʊ.ni.ə/
He is Macedonian.
Norway
/ˈnɔː.weɪ/
She is Norwegian.
Poland
/ˈpəʊ.lənd/
He is Polish.
Portugal
/ˈpɔː.tʃʊ.ɡəl/
She is Portuguese.
Romania
/ruˈmeɪ.ni.ə/
He is Romanian.
Russia
/ˈrʌʃ.ə/
She is Russian.
San Marino
/ˌsæn məˈriː.nəʊ/
He is Sammarinese.
Serbia
/ˈsɜː.bi.ə/
She is Serbian.
Slovakia
/sləʊˈvæk.i.ə/
He is Slovak.
Slovenia
/sləʊˈviː.ni.ə/
She is Slovenian.
Spain
/speɪn/
He is Spanish.
Sweden
/ˈswiː.dən/
She is Swedish.
Switzerland
/ˈswɪt.sə.lənd/
He is Swiss.
Ukraine
/juːˈkreɪn/
She is Ukrainian.
United Kingdom
/juˌnaɪ.tɪd ˈkɪŋ.dəm/
He is British.
Vatican City
/ˈvæt.ɪ.kən ˈsɪt.i/
She works at the Vatican.
Antigua and Barbuda
/ænˌtiː.ɡə ənd bɑːˈbjuː.də/
She is Antiguan.
Argentina
/ˌɑː.dʒənˈtiː.nə/
He is Argentinian.
Bahamas
/bəˈhɑː.məz/
She is Bahamian.
Barbados
/bɑːˈbeɪ.dɒs/
He is Barbadian.
Belize
/bəˈliːz/
She is Belizean.
Bolivia
/bəˈlɪv.i.ə/
He is Bolivian.
Brazil
/brəˈzɪl/
She is Brazilian.
Canada
/ˈkæn.ə.də/
He is Canadian.
Chile
/ˈtʃɪl.i/
She is Chilean.
Colombia
/kəˈlɒm.bi.ə/
He is Colombian.
Costa Rica
/ˌkɒs.tə ˈriː.kə/
She is Costa Rican.
Cuba
/ˈkjuː.bə/
He is Cuban.
Dominica
/ˌdɒm.ɪˈniː.kə/
She is Dominican.
Dominican Republic
/dəˌmɪn.ɪ.kən rɪˈpʌb.lɪk/
He is Dominican.
Ecuador
/ˈek.wə.dɔːr/
She is Ecuadorian.
El Salvador
/el ˈsæl.və.dɔːr/
He is Salvadoran.
Grenada
/ɡrəˈneɪ.də/
She is Grenadian.
Guatemala
/ˌɡwɑː.təˈmɑː.lə/
He is Guatemalan.
Guyana
/ɡaɪˈæn.ə/
She is Guyanese.
Haiti
/ˈheɪ.ti/
He is Haitian.
Honduras
/hɒnˈdjʊə.rəs/
She is Honduran.
Jamaica
/dʒəˈmeɪ.kə/
He is Jamaican.
Mexico
/ˈmek.sɪ.kəʊ/
She is Mexican.
Nicaragua
/ˌnɪk.əˈræɡ.juə/
He is Nicaraguan.
Panama
/ˈpæn.ə.mɑː/
She is Panamanian.
Paraguay
/ˈpær.ə.ɡwaɪ/
He is Paraguayan.
Peru
/pəˈruː/
She is Peruvian.
Saint Kitts and Nevis
/seɪnt ˌkɪts ənd ˈniː.vɪs/
He is Kittitian.
Saint Lucia
/seɪnt ˈluː.ʃə/
She is Saint Lucian.
Saint Vincent and the Grenadines
/seɪnt ˈvɪn.sənt/
He is Vincentian.
Suriname
/ˌsʊə.rɪˈnɑːm/
She is Surinamese.
Trinidad and Tobago
/ˌtrɪn.ɪ.dæd ənd təˈbeɪ.ɡəʊ/
He is Trinidadian.
United States
/juˌnaɪ.tɪd ˈsteɪts/
She is American.
Uruguay
/ˈjʊər.ə.ɡwaɪ/
He is Uruguayan.
Venezuela
/ˌven.əˈzweɪ.lə/
She is Venezuelan.
Australia
/ɒˈstreɪ.li.ə/
She is Australian.
Fiji
/ˈfiː.dʒiː/
He is Fijian.
Kiribati
/ˌkɪr.ɪˈbæs/
She is I-Kiribati.
Marshall Islands
/ˈmɑː.ʃəl ˈaɪ.ləndz/
He is Marshallese.
Micronesia
/ˌmaɪ.krəˈniː.ʒə/
She is Micronesian.
Nauru
/nɑːˈuː.ruː/
He is Nauruan.
New Zealand
/ˌnjuː ˈziː.lənd/
She is a New Zealander.
Palau
/pəˈlaʊ/
He is Palauan.
Papua New Guinea
/ˌpæp.u.ə ˌnjuː ˈɡɪn.i/
She is Papua New Guinean.
Samoa
/səˈməʊ.ə/
He is Samoan.
Solomon Islands
/ˈsɒl.ə.mən ˈaɪ.ləndz/
She is a Solomon Islander.
Tonga
/ˈtɒŋ.ə/
He is Tongan.
Tuvalu
/tuːˈvɑː.luː/
She is Tuvaluan.
Vanuatu
/ˌvæn.uˈɑː.tuː/
He is a Ni-Vanuatu.
Capital letters:
In English, nationalities and languages ALWAYS start with a capital letter: Spanish, French, Brazilian, Chinese. Never write "she is spanish" — always "she is Spanish".