Well, in Icelandic there are just two tenses: The past and present tense.
Icelandic however has six moods: The Indicative is the most common one and is mainly used in statements:
– Hann talar mikið - “he talks much”
– þið lesið bókina - “you read the book”
The Subjunctive is used to express hope, wish or something unreal:
– Þú læsir bókina er þú gætir - “you would read the book if you could”
– Ef ég væri sterkari lemdi ég hann - “if I was stronger I would hit him”
Subjunctive is also used with some conjunctions and in indirect speech:
– Þó hún sofi mikið er hún alltaf þreytt - “though she sleeps much she is always tired”
– Hann sagði að skipið færi á morgun - “he said that the ship would leave tomorrow”
The Imperative is used for commands and normally it is formed by the suffixes -du, -ðu or -tu, but they are derived from the personal pronoun þú “you”:
– Lestu bókina! - “read the book!”
– Komdu strax! - “come immediately!”
– Farðu! - “go!”.
The imperative plural has the same form as indicative and subjunctive:
– Lesið bókina! - “read the book!”
The present participle is formed by the suffix -andi and is uninflected:
– Þú kemur gangandi - “you come walking”
– Sýnið gangandi vegfarendum tillitssemi - “pay attention to walking passers-by”. The past participle is formed with auxiliaries like hafa “have” and geta “can”:
– Ég hef lesið bókina - “I have read the book”
– Ég get lesið bókina - “I can read the book”
In the passive voice the past participle agrees with the nominative subject in gender, number and case:
– Þeir (m. pl. nom) voru handteknir (m. pl. nom.) - “they were arrested”
– Þær (f. pl. nom.) voru handteknar (f. pl. nom.) - “they were arrested”
The Infinitive is formed by the suffix -a:
– Lesa - “to read”, koma - “to come”, skrifa - “to write”.
To make things interesting, nouns, adjectives, pronouns and numerals are declined for four cases; nominative, accusative, dative and genitive. Words are normally in the nominative unless they are governed by some other word or constituent in the sentence. Prepositions and verbs can assign accusative, dative and genitive and nouns can assign genitive.
So the word “horse” in Icelandic would be hestur, hest, hesti, hests, hesturinn, hestinum or hestsins, depending on the sentence… which should answer the OP’s question… or not - I got a little bit caried away, it seems.
…this has been “Icelandic and you”, tune in again tomorrow for more obscure grammar lessons you didn’t ask for.